Pancreatic stellate cells (PSCs) express cyclooxygenase-2 (COX-2) and pancreatic cancer stimulates COX-2 in PSCs

Arachidonic acid metabolism as a novel pathogenic factor in gastrointestinal cancers

Gastrointestinal (GI) cancers are a major global health burden, representing 20% of all cancer diagnoses and 22.5% of global cancer-related deaths. Their aggressive nature and resistance to treatment pose a significant challenge, with late-stage survival rates below 15% at five years. Therefore, there is an urgent need to delve deeper into the mechanisms of gastrointestinal cancer progression and optimize treatment strategies. Increasing evidence highlights the active involvement of abnormal arachidonic acid (AA) metabolism in various cancers. AA is a fatty acid mainly metabolized into diverse bioactive compounds by three enzymes: cyclooxygenase, lipoxygenase, and cytochrome P450 enzymes. Abnormal AA metabolism and altered levels of its metabolites may play a pivotal role in the development of GI cancers. However, the underlying mechanisms remain unclear. This review highlights a unique perspective by focusing on the abnormal metabolism of AA and its involvement in GI cancers. We summarize the latest advancements in understanding AA metabolism in GI cancers, outlining changes in AA levels and their potential role in liver, colorectal, pancreatic, esophageal, gastric, and gallbladder cancers. Moreover, we also explore the potential of targeting abnormal AA metabolism for future therapies, considering the current need to explore AA metabolism in GI cancers and outlining promising avenues for further research. Ultimately, such investigations aim to improve treatment options for patients with GI cancers and pave the way for better cancer management in this area.

Discovery of new thymol-3,4-disubstituted thiazole hybrids as dual COX-2/5-LOX inhibitors with in vivo proof

New thymol-3,4-disubstitutedthiazole hybrids were synthesised as dual COX-2/5-LOX inhibitors. Compounds 6b, 6d, 6e, and 6f displayed in vitro inhibitory activity against COX-2 (IC50= 0.037, 0.042, 0.046, and 0.039 µM) nearly equal to celecoxib (IC50= 0.045 µM). 6b, 6d, and 6f showed SI (379, 341, and 374, respectively) higher than that of celecoxib (327). 6a-l elicited in vitro 5-LOX inhibitory activity higher than quercetin. 6a-f, 6i-l, 7a, and 7c possessed in vivo inhibition of formalin induced paw edoema higher than celecoxib. 6a, 6b, 6f, 6h-l, and 7b showed gastrointestinal safety profile as celecoxib and diclofenac sodium in the population of fasted rats. Induced fit docking and molecular dynamics simulation predicted good fitting of 6b and 6f without changing the packing and globularity of the apo protein. In conclusion, 6b and 6f achieved the target goal as multitarget inhibitors of inflammation.

The Role of Fatty Acid Metabolism, the Related Potential Biomarkers, and Targeted Therapeutic Strategies in Gastrointestinal Cancers

Gastrointestinal cancer has emerged as a significant global health concern due to its high incidence and mortality, limited effectiveness of early detection, suboptimal treatment outcomes, and poor prognosis. Metabolic reprogramming is a prominent feature of cancer, and fatty acid metabolism assumes a pivotal role in bridging glucose metabolism and lipid metabolism. Fatty acids play important roles in cellular structural composition, energy supply, signal transduction, and other lipid-related processes. Changes in the levels of fatty acid metabolite may indicate the malignant transformation of gastrointestinal cells, which have an impact on the prognosis of patients and can be used as a marker to monitor the efficacy of anticancer therapy. Therefore, targeting key enzymes involved in fatty acid metabolism, either as monotherapy or in combination with other agents, is a promising strategy for anticancer treatment. This article reviews the potential mechanisms of fatty acid metabolism disorders in the occurrence and development of gastrointestinal tumors, and summarizes the related potential biomarkers and anticancer strategies.

Arachidonate 15-lipoxygenase-mediated production of Resolvin D5n-3 DPA abrogates pancreatic stellate cell-induced cancer cell invasion

Activation of pancreatic stellate cells (PSCs) to cancer-associated fibroblasts (CAFs) is responsible for the extensive desmoplastic reaction observed in PDAC stroma: a key driver of pancreatic ductal adenocarcinoma (PDAC) chemoresistance leading to poor prognosis. Specialized pro-resolving mediators (SPMs) are prime modulators of inflammation and its resolution, traditionally thought to be produced by immune cells. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based lipid mediator profiling PSCs as well as primary human CAFs express enzymes and receptors to produce and respond to SPMs. Human PSC/CAF SPM secretion profile can be modulated by rendering these cells activated [transforming growth factor beta (TGF-β)] or quiescent [all-trans retinoic acid (ATRA)]. ATRA-induced nuclear translocation of arachidonate-15-lipoxygenase (ALOX15) was linked to increased production of n-3 docosapentaenoic acid-derived Resolvin D5 (RvD5n-3 DPA), among other SPMs. Inhibition of RvD5n-3 DPA formation increases cancer cell invasion, whereas addback of this molecule reduced activated PSC-mediated cancer cell invasion. We also observed that circulating concentrations of RvD5n-3 DPA levels were decreased in peripheral blood of metastatic PDAC patients when compared with those measured in plasma of non-metastatic PDAC patients. Together, these findings indicate that RvD5n-3 DPA may regulate cancer-stroma cross-talk and invasion.

Prognostic Value of COX-2, NF-κB, and Sp1 Tissue Expressions in Pancreatic Ductal Adenocarcinoma: A Systematic Review and Meta-analysis

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is deadly cancer with a poor prognosis. Molecular prognostic markers are needed to predict the patient's survival. The cyclooxygenase-2 enzyme (COX-2) and its 2 major transcription factors--nuclear factorkappa B (NF-κB) and specificity protein 1 (Sp1)--are activated during inflammation caused by neoplasia. Several studies have investigated the association between the COX-2, NF-κB, and Sp1 tissue expressions with the patient's overall survival. Therefore, we conducted this systematic review and meta-analysis to evaluate those studies.

METHODS

We searched for relevant articles from the MEDLINE database through June 2020. Studies were eligible if they included dichotomized tissue protein expression status and the overall survival as the outcome. We used RevMan and ProMeta programs to perform the meta-analysis.

RESULTS

We identified 11 eligible studies. The meta-analysis showed that COX-2 tissue expression was associated with decreased overall survival (crude HR = 1.35; 95% CI, 1.05-1.74), although the result was not significant when controlling for other covariates. The NF-κB tissue expression was associated with decreased overall survival (crude HR = 2.18; 95% CI, 1.49-3.18), although it was not significant when controlling for other covariates. The Sp1 tissue expression showed significantly decreased overall survival even when adjusted with other covariates (aHR = 3.47; 95% CI, 1.52-7.94). The limitations included searching only for English publications and the substantial heterogeneity among the studies.

CONCLUSION

COX-2, NF-κB, and Sp1 tissue expressions have the potential to be used as prognostic markers in PDAC. Further studies are still needed to clarify the associations.

Molecular mechanisms of pancreatic myofibroblast activation in chronic pancreatitis and pancreatic ductal adenocarcinoma

Pancreatic fibrosis (PF) is an essential component of the pathobiology of chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC). Activated pancreatic myofibroblasts (PMFs) are crucial for the deposition of the extracellular matrix, and fibrotic reaction in response to sustained signaling. Consequently, understanding of the molecular mechanisms of PMF activation is not only critical for understanding CP and PDAC biology but is also a fertile area of research for the development of novel therapeutic strategies for pancreatic pathologies. This review analyzes the key signaling events that drive PMF activation including, initiating signals from transforming growth factor-β1, platelet derived growth factor, as well as other microenvironmental cues, like hypoxia and extracellular matrix rigidity. Further, we discussed the intracellular signal events contributing to PMF activation, and crosstalk with different components of tumor microenvironment. Additionally, association of epidemiologically established risk factors for CP and PDAC, like alcohol intake, tobacco exposure, and metabolic factors with PMF activation, is discussed to comprehend the role of lifestyle factors on pancreatic pathologies. Overall, this analysis provides insight into the biology of PMF activation and highlights salient features of this process, which offer promising therapeutic targets.

Neoplastic-Stromal Cell Cross-talk Regulates Matrisome Expression in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a highly desmoplastic reaction, warranting intense cancer-stroma communication. In this study, we interrogated the contribution of the BET family of chromatin adaptors to the cross-talk between PDAC cells and the tumor stroma. Short-term treatment of orthotopic xenograft tumors with CPI203, a small-molecule inhibitor of BET proteins, resulted in broad changes in the expression of genes encoding components of the extracellular matrix (matrisome) in both cancer and stromal cells. Remarkably, more than half of matrisome genes were expressed by cancer cells. In vitro cocultures of PDAC cells and cancer-associated fibroblasts (CAF) demonstrated that matrisome expression was regulated by BET-dependent cancer-CAF cross-talk. Disrupting this cross-talk in vivo resulted in diminished growth of orthotopic patient-derived xenograft tumors, reduced proliferation of cancer cells, and changes in collagen structure consistent with that of patients who experienced better survival. Examination of matrisome gene expression in publicly available data sets of 573 PDAC tumors identified a 65-gene signature that was able to distinguish long- and short-term PDAC survivors. Importantly, the expression of genes predictive of short-term survival was diminished in the cancer cells of orthotopic xenograft tumors of mice treated with CPI203. Taken together, these results demonstrate that inhibiting the activity BET proteins results in transcriptional and structural differences in the matrisome are associated with better patient survival. IMPLICATIONS: These studies highlight the biological relevance of the matrisome program in PDAC and suggest targeting of epigenetically driven tumor-stroma cross-talk as a potential therapeutic avenue.

Stellate Cells in the Tumor Microenvironment

As tumor microenvironments share many of the same qualities as chronic wounds, attention is turning to the wound-repair cells that support the growth of cancerous cells. Stellate cells are star-shaped cells that were first discovered in the perisinusoidal spaces in the liver and have been found to support wound healing by the secretion of growth factors and extracellular matrix. They have since been also found to serve a similar function in the pancreas. In both organs, the wound-healing process may become dysregulated and lead to pathological fibrosis (also known as cirrhosis in the liver). In recent years there has been increasing attention paid to the role of these cells in tumor formation and progression. They may be a factor in initiating the first steps of carcinogenesis such as with liver cirrhosis and hepatocellular carcinoma and also contribute to continued tumor growth, invasion, metastasis, evasion of the immune system, and resistance to chemotherapy, in cancers of both the liver and pancreas. In this chapter we aim to review the structure and function of hepatic and pancreatic stellate cells and their contributions to the tumor microenvironment in their respective cancers and also discuss potential new targets for cancer therapy based on our new understanding of these vital components of the tumor stroma.

Pancreatic stellate cells: Aiding and abetting pancreatic cancer progression

Tumour-stromal interactions have now been acknowledged to play a major role in pancreatic cancer (PC) progression. The abundant collagenous stroma is produced by a specific cell type in the pancreas-the pancreatic stellate cell (PSC). Pancreatic stellate cells (PSCs) are a unique resident cell type of pancreas and with a critical role in both healthy and diseased pancreas. Accumulating evidence indicates that PSCs interact closely with cancer cells as well as with other cell types of the stroma such as immune cells, endothelial cells and neuronal cells, to set up a growth permissive microenvironment for pancreatic tumours, which facilitates local tumour growth as well as distant metastasis. Consequently, recent work in the field has focused on the development of novel therapeutic approaches targeting the stroma to inhibit PC progression. Such a multi-pronged approach targeting both tumour and stromal elements of PC has been successfully applied in pre-clinical settings. The challenge now is to translate the pre-clinical findings into the clinical setting to achieve better outcomes for pancreatic cancer patients.

The Paradoxical Web of Pancreatic Cancer Tumor Microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is increasing in incidence and is projected to become the second leading cause of cancer death in the United States. Despite significant advances in understanding the disease, there has been minimal increase in PDAC patient survival. PDAC tumors are unique in the fact that there is significant desmoplasia. This generates a large stromal compartment composed of immune cells, inflammatory cells, growth factors, extracellular matrix, and fibroblasts, comprising the tumor microenvironment (TME), which may represent anywhere from 15% to 85% of the tumor. It has become evident that the TME, including both the stroma and extracellular component, plays an important role in tumor progression and chemoresistance of PDAC. This review will discuss the multiple components of the TME, their specific impact on tumorigenesis, and the multiple therapeutic targets.

Impact of the secretome of activated pancreatic stellate cells on growth and differentiation of pancreatic tumour cells

Pancreatic ductal adenocarcinoma (PDAC) exists in a complex desmoplastic microenvironment. As part of it, pancreatic stellate cells (PSCs) provide a fibrotic niche, stimulated by a dynamic communication between activated PSCs and tumour cells. Investigating how PSCs contribute to tumour development and for identifying proteins that the cells secrete during cancer progression, we studied by means of complex antibody microarrays the secretome of activated PSCs. A large number of secretome proteins were associated with cancer-related functions, such as cell apoptosis, cellular growth, proliferation and metastasis. Their effect on tumour cells could be confirmed by growing tumour cells in medium conditioned with activated PSC secretome. Analyses of the tumour cells' proteome and mRNA revealed a strong inhibition of tumour cell apoptosis, but promotion of proliferation and migration. Many cellular proteins that exhibited variations were found to be under the regulatory control of eukaryotic translation initiation factor 4E (eIF4E), whose expression was triggered in tumour cells grown in the secretome of activated PSCs. Inhibition by an eIF4E siRNA blocked the effect, inhibiting tumour cell growth in vitro. Our findings show that activated PSCs acquire a pro-inflammatory phenotype and secret proteins that stimulate pancreatic cancer growth in an eIF4E-dependent manner, providing further insight into the role of stromal cells in pancreatic carcinogenesis and cancer progression.

Palmatine suppresses glutamine-mediated interaction between pancreatic cancer and stellate cells through simultaneous inhibition of survivin and COL1A1

Reciprocal interaction between pancreatic stellate cells (PSCs) and cancer cells (PCCs) in the tumor microenvironment (TME) promotes tumor cell survival and progression to lethal, therapeutically resistant pancreatic cancer. The goal of this study was to test the ability of Palmatine (PMT) to disrupt this reciprocal interaction in vitro and examine the underlying mechanism of interaction. We show that PSCs secrete glutamine into the extracellular environment under nutrient deprivation. PMT suppresses glutamine-mediated changes in GLI signaling in PCCs resulting in the inhibition of growth and migration while inducing apoptosis by inhibition of survivin. PMT-mediated inhibition of (glioma-associated oncogene 1) GLI activity in stellate cells leads to suppression (collagen type 1 alpha 1) COL1A1 activation. Remarkably, PMT potentiated gemcitabine’s growth inhibitory activity in PSCs, PCCs and inherently gemcitabine-resistant pancreatic cancer cells. This is the first study that shows the ability of PMT to inhibit growth of PSCs and PCCs either alone or in combination with gemcitabine. These studies warrant additional investigations using preclinical models to develop PMT as an agent for clinical management of pancreatic cancer.

Shattering the castle walls: Anti-stromal therapy for pancreatic cancer

Despite the availability of potent chemotherapy regimens, such as 5-fluorouracil, folinic acid, irinotecan, and oxaliplatin (FOLFIRINOX) and nab-paclitaxel plus gemcitabine, treatment outcomes in metastatic pancreatic cancer (PC) remain unsatisfactory. The presence of an abundant fibrous stroma in PC is considered a crucial factor for its unfavorable condition. Apparently, stroma acts as a physical barrier to restrict intratumoral cytotoxic drug penetration and creates a hypoxic environment that reduces the efficacy of radiotherapy. In addition, stroma plays a vital supportive role in the development and progression of PC, which has prompted researchers to assess the potential benefits of agents targeting several cellular (e.g., stellate cells) and acellular (e.g., hyaluronan) elements of the stroma. This study aims to briefly review the primary structural properties of PC stroma and its interaction with cancer cells and summarize the current status of anti-stromal therapies in the management of metastatic PC.

New benzothiophene derivatives as dual COX-1/2 and 5-LOX inhibitors: synthesis, biological evaluation and docking study

Aim: Simultaneous inhibition of 5-LOX/COX may enhance anti-inflammatory effects and reduce side effects. Hence, synthesis of novel dual inhibitors of 5-LOX/COX is an important strategy for treatment of inflammation. Results/methodology: The target compounds were designed to hybridize benzothiophene scaffold or its bioisostere benzofuran with various anti-inflammatory pharmacophore hetercycles through different atoms spacers. Compounds 4a, 4c, 4d, 5b, 7a, showed significant in vitro LOX inhibitory activity higher than that of meclofenamate sodium. Compounds 4b, 4e, 4f, 5a exhibited significant in vitro COX-2 inhibition higher than celecoxib and in vitro LOX inhibitory activity twice that of reference. These compounds elicited significant in vivo anti-inflammatory activities higher than celecoxib in formalin-induced paw edema test. Compound 4e exhibited gastrointestinal safety profile as celecoxib. The results were also consistent with the docking studies. Conclusion: Compound 4e could be considered as structural lead for the development of a new class of anti-inflammatory agents with better safety profile.

Targeting stroma in pancreatic cancer: Promises and failures of targeted therapies

Desmoplasia or abundant fibrotic stroma is a typical property of most malignancies, which has a great effect on tumorigenesis, angiogenesis, and resistance to therapy. The activated stroma cells comprises several cell types including endothelial cells, nerve cells, inflammatory/macrophages cells, stellate cells, and extracellular matrix. In other word, the interactions of cancer-stroma modulate tumorigenesis, therapy resistance, and poor delivery of drugs. Therefore, targeting the tumor stroma in combination with conventional chemotherapeutic agents could provide a promising approach in the treatment of pancreatic cancer. This review summarizes the current knowledge about pancreatic stellate cells, targeting stroma compartments with particular emphasis on preclinical, and clinical trials on targeting of stroma as an option in pancreatic cancer treatment.

Nonsteroidal anti-inflammatory drugs, statins, and pancreatic cancer risk: a population-based case-control study

PURPOSE

Studies suggest that aspirin, other nonsteroidal anti-inflammatory drugs (NSAIDs), and statins may reduce risk of some cancers. However, findings have been conflicting as to whether these agents reduce the risk of pancreatic cancer.

METHODS

We used data from the Queensland Pancreatic Cancer Study, a population-based case-control study. In total, 704 cases and 711 age- and sex-matched controls were recruited. Participants completed an interview in which they were asked about history of NSAID and statin use. We included 522 cases and 653 controls who had completed the medication section of the interview in this analysis. Unconditional multivariable logistic regression was used to estimate associations between medication use and pancreatic cancer.

RESULTS

We found no consistent evidence of an association between use of NSAIDs or statins and risk of pancreatic cancer. There was some suggestion of a protective effect in infrequent users of selective COX-2 inhibitors, but no association in more frequent users. We did not find evidence of protective effects in analyses stratified by sex, smoking status, time between diagnosis and interview, or presence/absence of metastases.

CONCLUSIONS

Overall, our results do support the hypothesis that use of NSAIDs or statins may reduce the odds of developing pancreatic cancer.

NS-398 promotes pancreatic cancer cell invasion by CD147 and MMP-2 via the activation of P38

The overexpression or abnormal activation of cyclo‑oxygenase‑2 (COX‑2) has been reported in pancreatic cancer cells. NS‑398, a selective inhibitor of COX‑2, is unable to inhibit pancreatic cancer cell proliferation, as determined by a Cell Counting Kit 8 assay. However, it does increase cancer cell invasiveness, and therefore the invasiveness of the PANC‑1 cells was determined, along with the activation of P38, which was assessed by western blotting. In the present study, to evaluate the mechanisms underlying the action of NS‑398 in pancreatic cancer cells, PANC‑1 cells were treated with NS‑398, and the invasion signaling pathways of cluster of differentiation (CD)147‑matrix metalloproteinase (MMP)‑2 and mitogen‑activated protein kinases were evaluated. The results showed that NS‑398‑induced the expression of CD147 and MMP‑2 via the activation of P38, which was involved in antiproliferative activity and induced pancreatic cancer cell invasiveness. The PANC‑1 cells were also co‑treated with CD147 small interfering (si)RNA and NS‑398, and it was found that the NS‑398‑induced activation of P38 was not inhibited by CD147 siRNA, however, the expression of MMP‑2 was inhibited. CD147 siRNA inhibited the invasiveness of the pancreatic cancer cells induced by NS‑398, but also restored NS‑398‑induced antiproliferative activity. These data indicated that P38 in the pancreatic cancer cells was non‑specifically activated by NS‑398. This activation induced the expression of CD147‑MMP‑2, opposed the antiproliferative activity of NS‑398 and increased the invasiveness of the PANC‑1 cells.

Key role of pancreatic stellate cells in pancreatic cancer

Pancreatic stellate cells (PSCs) are responsible for producing the collagenous stroma in pancreatic cancer. Findings from the majority of in vitro and in vivo studies to date indicate that PSCs interact with cancer cells as well as with other cellular elements in the stroma including immune cells, endothelial cells and neuronal cells to set up a growth permissive microenvironment for pancreatic tumours. However, two recent studies reporting a protective effect of myofibroblasts in pancreatic cancer have served to remind researchers of the possibility that the role of PSCs in this disease may be context and time-dependent, such that any possible early protective role of PSCs is subverted in later stages by the ability of cancer cells to turn PSCs into cancer-promoting aides. This concept is supported by the development in recent years of several novel therapeutic approaches targeting the stroma that have been successfully applied in pre-clinical settings to inhibit disease progression. A multi-pronged approach aimed at tumour cells as well as stromal elements may be the key to achieving better clinical outcomes in patients with pancreatic cancer.

Pancreatic cancer: The microenvironment needs attention too!

The abundant stromal/desmoplastic reaction, a characteristic feature of a majority of pancreatic adenocarcinomas (PDAC), has only recently been receiving some attention regarding its possible role in the pathobiology of pancreatic cancer. It is now well established that the cells predominantly responsible for producing the collagenous stroma are pancreatic stellate cells (PSCs). In addition to extracellular matrix proteins, the stroma also exhibits cellular elements including, immune cells, endothelial cells and neural cells. Evidence is accumulating to indicate the presence of significant interactions between PSCs and cancer cells as well as between PSCs and other cell types in the stroma. The majority of research reports to date, using in vitro and in vivo approaches, suggest that these interactions facilitate local growth as well as distant metastasis of pancreatic cancer, although a recent study using animals depleted of myofibroblasts has raised some questions regarding the central role of myofibroblasts in cancer progression. Nonetheless, novel therapeutic strategies have been assessed, mainly in the pre-clinical setting, in a bid to interrupt stromal-tumour interactions and inhibit disease progression. The next important challenge is for the translation of such pre-clinical strategies to the clinical situation so as to improve the outcome of patients with pancreatic cancer.

Smad4 loss synergizes with TGFα overexpression in promoting pancreatic metaplasia, PanIN development, and fibrosis

AIMS

While overexpression of TGFα has been reported in human pancreatic ductal adenocarcinoma (PDAC), mice with overexpressed TGFα develop premalignant pancreatic acinar-to-ductal metaplasia (ADM) but not PDAC. TGF-β signaling pathway is pivotal to the development of PDAC and tissue fibrosis. Here we sought to investigate the interplay between TGFα and TGF-β signaling in pancreatic tumorigenesis and fibrosis, namely via Smad4 inactivation.

METHODS

The MT-TGFα mouse was crossed with a new Smad4 conditional knock-out mouse (Smad4flox/flox;p48-Cre or S4) to generate Smad4flox/flox;MT-TGFα;p48-Cre (STP). After TGFα overexpression was induced with zinc sulfate water for eight months, the pancreata of the STP, MT-TGFα, and S4 mice were examined for tumor development and fibrotic responses. PanIN lesions and number of ducts were counted, and proliferation was measured by Ki67 immunohistochemistry (IHC). Qualitative analysis of fibrosis was analyzed by Trichrome Masson and Sirius Red staining, while vimentin was used for quantification. Expression analyses of fibrosis, pancreatitis, or desmoplasia associated markers (α-SMA, Shh, COX-2, Muc6, Col1a1, and Ctgf) were performed by IHC and/or qRT-PCR.

RESULTS

Our STP mice exhibited advanced ADM, increased fibrosis, increased numbers of PanIN lesions, overexpression of chronic pancreatitis-related marker Muc6, and elevated expression of desmoplasia-associated marker Col1A1, compared to the MT-TGFα mice. The inactivation of Smad4 in the exocrine compartment was responsible for both the enhanced PanIN formation and fibrosis in the pancreas. The phenotype of the STP mice represents a transient state from ADMs to PanINs, closely mimicking the interface area seen in human chronic pancreatitis associated with PDAC.

CONCLUSION

We have documented a novel mouse model, the STP mice, which displayed histologic presentations reminiscent to those of human chronic pancreatitis with signs of early tumorigenesis. The STP mice could be a suitable animal model for interrogating the transition of chronic pancreatitis to pancreatic cancer.

Pancreatic ductal adenocarcinoma: From genetics to biology to radiobiology to oncoimmunology and all the way back to the clinic

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer death. Despite improvements in the clinical management, the prognosis of PDAC remains dismal. In the present comprehensive review, we will examine the knowledge of PDAC genetics and the new insights into human genome sequencing and clonal evolution. Additionally, the biology and the role of the stroma in tumour progression and response to treatment will be presented. Furthermore, we will describe the evidence on tumour chemoresistance and radioresistance and will provide an overview on the recent advances in PDAC metabolism and circulating tumour cells. Next, we will explore the characteristics and merits of the different mouse models of PDAC. The inflammatory milieu and the immunosuppressive microenvironment mediate tumour initiation and treatment failure. Hence, we will also review the inflammatory and immune escaping mechanisms and the new immunotherapies tested in PDAC. A better understanding of the different mechanisms of tumour formation and progression will help us to identify the best targets for testing in future clinical studies of PDAC.

Pancreatic cancer and its stroma: A conspiracy theory

Pancreatic cancer is characterised by a prominent desmoplastic/stromal reaction that has received little attention until recent times. Given that treatments focusing on pancreatic cancer cells alone have failed to significantly improve patient outcome over many decades, research efforts have now moved to understanding the pathophysiology of the stromal reaction and its role in cancer progression. In this regard, our Group was the first to identify the cells (pancreatic stellate cells, PSCs) that produced the collagenous stroma of pancreatic cancer and to demonstrate that these cells interacted closely with cancer cells to facilitate local tumour growth and distant metastasis. Evidence is accumulating to indicate that stromal PSCs may also mediate angiogenesis, immune evasion and the well known resistance of pancreatic cancer to chemotherapy and radiotherapy. This review will summarise current knowledge regarding the critical role of pancreatic stellate cells and the stroma in pancreatic cancer biology and the therapeutic approaches being developed to target the stroma in a bid to improve the outcome of this devastating disease.

Pancreatic stellate cells and pancreas cancer: current perspectives and future strategies

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant disease with a very poor prognosis. To date patient outcomes have not improved principally due to the limited number of patients suitable for surgical resections and the radiation and chemotherapy resistance of these tumours. In the last decade, a failure of conventional therapies has forced researchers to re-examine the environment of PDAC. The tumour environment has been demonstrated to consist of an abundance of stroma containing many cells but predominantly pancreatic stellate cells (PSCs). Recent research has focused on understanding the interaction between PSCs and PDAC cells in vitro and in vivo. It is believed that the interaction between these cells is responsible for supporting tumour growth, invasion and metastasis and creating the barrier to delivery of chemotherapeutics. Novel approaches which focus on the interactions between PDAC and PSCs which sustain the tumour microenvironment may achieve significant patient benefits. This manuscript reviews the current evidence regarding PSCs, their interaction with PDAC cells and the potential implication this may have for future therapies.

METHODS

A PubMed search was carried out for the terms 'pancreas cancer' OR 'pancreatic cancer', AND 'pancreatic stellate cells', NOT 'hepatic stellate cells'. All studies were screened and assessed for their eligibility and manuscripts exploring the relationship between PSCs and PDAC were included. The studies were subdivided into in vitro and in vivo groups.

RESULTS

One hundred and sixty-six manuscripts were identified and reduced to seventy-three in vitro and in vivo studies for review. The manuscripts showed that PDAC cells and PSCs interact with each other to enhance proliferation, reduce apoptosis and increase migration and invasion of cancer cells. The pathways through which they facilitate these actions provide potential targets for future novel therapies.

CONCLUSION

There is accumulating evidence supporting the multiple roles of PSCs in establishing the tumour microenvironment and supporting the survival of PDAC. To further validate these findings there is a need for greater use of physiologically relevant models of pancreatic cancer in vitro such as three dimensional co-cultures and the use of orthotopic and genetically engineered murine (GEM) models in vivo.

Inhibitory effects of prostaglandin E2 on collagen synthesis and cell proliferation in human stellate cells from pancreatic head adenocarcinoma

BACKGROUND

Several studies have described an increased cyclooxygenase-2 (COX-2) expression in pancreatic cancer, but the role of COX-2 in tumour development and progression is not clear. The aim of the present study was to examine expression of COX-2 in cancer cells and stromal cells in pancreatic cancer specimens, and to explore the role of PGE2 in pancreatic stellate cell proliferation and collagen synthesis.

METHODS

Immunohistochemistry and immunofluorescence was performed on slides from whole sections of tissue blocks using antibodies against COX-2 and α-smooth muscle actin (αSMA). Pancreatic stellate cells (PSC) were isolated from surgically resected tumour tissue by the outgrowth method. Cells were used between passages 4 and 8. Collagen synthesis was determined by [(3)H]-proline incorporation, or by enzyme immunoassay measurement of collagen C-peptide. DNA synthesis was measured by incorporation of [(3)H]-thymidine in DNA. Cyclic AMP (cAMP) was determined by radioimmunoassay. Collagen 1A1 mRNA was determined by RT-qPCR.

RESULTS

Immunohistochemistry staining showed COX-2 in pancreatic carcinoma cells, but not in stromal cells. All tumours showed positive staining for αSMA in the fibrotic stroma. Cultured PSC expressed COX-2, which could be further induced by interleukin-1β (IL-1β), epidermal growth factor (EGF), thrombin, and PGE2, but not by transforming growth factor-β1 (TGFβ). Indirect coculture with the adenocarcinoma cell line BxPC-3, but not HPAFII or Panc-1, induced COX-2 expression in PSC. Treatment of PSC with PGE2 strongly stimulated cAMP accumulation, mediated by EP2 receptors, and also stimulated phosphorylation of extracellular signal-regulated kinase (ERK). Treatment of PSC with PGE2 or forskolin suppressed both TGFβ-stimulated collagen synthesis and PDGF-stimulated DNA synthesis.

CONCLUSIONS

The present results show that COX-2 is mainly produced in carcinoma cells and suggest that the cancer cells are the main source of PGE2 in pancreatic tumours. PGE2 exerts a suppressive effect on proliferation and fibrogenesis in pancreatic stellate cells. These effects of PGE2 are mediated by the cAMP pathway and suggest a role of EP2 receptors.

Stars and stripes in pancreatic cancer: role of stellate cells and stroma in cancer progression

Pancreatic cancer is a devastating disease with an unacceptably high mortality to incidence ratio. Traditional therapeutic approaches such as surgery in combination with chemo- or radiotherapy have had limited efficacy in improving the outcome of this disease. Up until just under a decade ago, the prominent desmoplastic reaction which is a characteristic of the majority of pancreatic ductal adenocarcinomas (PDAC) had been largely ignored. However, since the identification of the pancreatic stellate cell (PSC) as the key cell responsible for the production of the collagenous stroma in PDAC, increasing attention has been paid to the role of the stromal reaction in pancreatic cancer pathobiology. There is now compelling evidence that PSCs interact not only with cancer cells themselves, but with several other cell types in the stroma (endothelial cells, immune cells, and possibly neuronal cells) to promote cancer progression. This review summarizes current knowledge in the field about the influence of PSCs and the stromal microenvironment on cancer behavior and discusses novel therapeutic approaches which reflect an increasing awareness amongst clinicians and researchers that targeting cancer cells alone is no longer sufficient to improve patient outcome and that combinatorial treatments targeting the stroma as well as the cancer cells will be required to change the clinical course of this disease.

Celecoxib analogs bearing benzofuran moiety as cyclooxygenase-2 inhibitors: design, synthesis and evaluation as potential anti-inflammatory agents

Novel series of celecoxib analogs endowed with benzofuran moiety 3a-e and 9a-d were synthesized and evaluated for COX-1/COX-2 inhibitory activity in vitro. The most potent and selective COX-2 inhibitors - compounds 3c, 3d, 3e, 9c and 9d - were assessed for their anti-inflammatory activity and ulcerogenic liability in vivo. The 3-(pyridin-3-yl)pyrazole derivatives 3c and 3e exhibited the highest anti-inflammatory activity, that is equipotent to celecoxib. Furthermore, the tested compounds proved to have better gastric safety profile compared to celecoxib. In particular, compound 3e demonstrated about 40% reduction in ulcerogenic potential relative to the reference drug. Finally, molecular docking simulation of the new compounds in COX-2 active site and drug likeness studies showed good agreement with the obtained pharmaco-biological results.

Pancreatic stellate cells promote hapto-migration of cancer cells through collagen I-mediated signalling pathway

Background:

Pancreatic stellate cells (PSCs) promote metastasis as well as local growth of pancreatic cancer. However, the factors mediating the effect of PSCs on pancreatic cancer cells have not been clearly identified.

Methods:

We used a modified Boyden chamber assay as an in vitro model to investigate the role of PSCs in migration of Panc1 and UlaPaCa cells and to identify the underlying mechanisms.

Results:

PSC supernatant (PSC-SN) dose-dependently induced the trans-migration of Panc1 and UlaPaCa cells, mainly via haptokinesis and haptotaxis, respectively. In contrast to poly-L-lysine or fibronectin, collagen I resembled PSC-SN with respect to its effect on cancer cell behaviours, including polarised morphology, facilitated adhesion, accelerated motility and stimulated trans-migration. Blocking antibodies against integrin α2/β1 subunits significantly attenuated PSC-SN- or collagen I-promoted cell trans-migration and adhesion. Moreover, both PSC-SN and collagen I induced the formation of F-actin and focal adhesions in cells, which was consistent with the constantly enhanced phosphorylation of focal adhesion kinase (FAK, Tyr397). Inhibition of FAK function by an inhibitor or small interference RNAs significantly diminished the effect of PSC-SN or collagen I on haptotaxis/haptokinesis of pancreatic cancer cells.

Conclusion:

Collagen I is the major mediator for PSC-SN-induced haptokinesis of Panc1 and haptotaxis of UlaPaCa by activating FAK signalling via binding to integrin α2β1.

The stromal compartments in pancreatic cancer: are there any therapeutic targets?

Pancreatic ductal adenocarcinoma (PDAC) is characterised by an abundant stromal response also known as a desmoplastic reaction. Pancreatic Stellate Cells have been identified as playing a key role in pancreatic cancer desmoplasia. There is accumulating evidence that the stroma contributes to tumour progression and to the low therapeutic response of PDAC patients. In this review we described the main actors of the desmoplastic reaction within PDAC and novel therapeutic approaches that are being tested to block the detrimental function of the stroma.

A starring role for stellate cells in the pancreatic cancer microenvironment

Pancreatic ductal adenocarcinoma is a devastating disease, and patient outcomes have not improved in decades. Treatments that target tumor cells have largely failed. This could be because research has focused on cancer cells and the influence of the stroma on tumor progression has been largely ignored. The focus of pancreatic cancer research began to change with the identification of pancreatic stellate cells, which produce the pancreatic tumor stroma. There is compelling in vitro and in vivo evidence for the influence of pancreatic stellate cells on pancreatic cancer development; several recent preclinical studies have reported encouraging results with approaches designed to target pancreatic stellate cells and the stroma. We review the background and recent advances in these areas, along with important areas of future research that could improve therapy.

Prostaglandin E2 regulates pancreatic stellate cell activity via the EP4 receptor

OBJECTIVES

Pancreatic stellate cells are source of dense fibrotic stroma, a constant pathological feature of chronic pancreatitis and pancreatic adenocarcinoma. We observed correlation between levels of cyclooxygenase 2 (COX-2) and its product prostaglandin E2 (PGE2) and the extent of pancreatic fibrosis. The aims of this study were to delineate the effects of PGE2 on immortalized human pancreatic stellate cells (HPSCs) and to identify the receptor involved.

METHODS

Immunohistochemistry, reverse transcription-polymerase chain reaction and quantitative reverse transcription-polymerase chain reaction were used to assess COX-2, extracellular matrix, and matrix metalloproteinase gene expression. Eicosanoid profile was determined by liquid chromatography-tandem mass spectrometry. Human pancreatic stellate cell proliferation was assessed by MTS assay, migration by Boyden chamber assay, and invasion using an invasion chamber. Transient silencing was obtained by small interfering RNA.

RESULTS

Human pancreatic stellate cells express COX-2 and synthesize PGE2. Prostaglandin E2 stimulated HPSC proliferation, migration, and invasion and stimulated expression of both extracellular matrix and matrix metalloproteinase genes. Human pancreatic stellate cells expressed all 4 EP receptors. Only blocking the EP4 receptor resulted in abrogation of PGE2-mediated HPSC activation. Specificity of EP4 for the effects of PGE2 on stellate cells was confirmed using specific antagonists.

CONCLUSIONS

Our data indicate that PGE2 regulates pancreatic stellate cell profibrotic activities via EP4 receptor, thus suggesting EP4 receptor as useful therapeutic target for pancreatic cancer to reduce desmoplasia.

Tumor-stromal interactions in pancreatic cancer

Pancreatic adenocarcinoma has one of the worse prognoses of any cancer with a 5-year survival of only 3%. Pancreatic cancer displays one of the most prominent stromal reactions of all tumors and it is evident that this is a key contributing factor to disease outcome. The tumor microenvironment of pancreatic cancer harbors a wide spectrum of cell types and a complex network of mechanisms which all serve to promote tumor progression. It is clear that the symbiotic relationship between pancreatic cancer cells and stellate cells is the chief factor creating this unique tumor milieu. Pancreatic stellate cells play critical roles in evasion of cancer cell apoptosis, invasion and metastases, angiogenesis, and promotion of an immunosuppressive environment, all key hallmarks of malignancy. Existing treatments for pancreatic cancer focus on targeting the cancer cells rather than the whole tumor, of which cancer cells represent a small proportion. It is now increasingly evident that research targeted towards the interactions between these cell types, ideally at an early stage of tumor development, is imperative in order to propel the way forward to more effective treatments.

Pancreatic stellate cells: a starring role in normal and diseased pancreas

While the morphology and function of cells of the exocrine and endocrine pancreas have been studied over several centuries, one important cell type in the gland, the pancreatic stellate cell (PSC), had remained undiscovered until as recently as 20 years ago. Even after its first description in 1982, it was to be another 16 years before its biology could begin to be studied, because it was only in 1998 that methods were developed to isolate and culture PSCs from rodent and human pancreas. PSCs are now known to play a critical role in pancreatic fibrosis, a consistent histological feature of two major diseases of the pancreas—chronic pancreatitis and pancreatic cancer. In health, PSCs maintain normal tissue architecture via regulation of the synthesis and degradation of extracellular matrix (ECM) proteins. Recent studies have also implied other functions for PSCs as progenitor cells, immune cells or intermediaries in exocrine pancreatic secretion in humans. During pancreatic injury, PSCs transform from their quiescent phase into an activated, myofibroblast-like phenotype that secretes excessive amounts of ECM proteins leading to the fibrosis of chronic pancreatitis and pancreatic cancer. An ever increasing number of factors that stimulate and/or inhibit PSC activation via paracrine and autocrine pathways are being identified and characterized. It is also now established that PSCs interact closely with pancreatic cancer cells to facilitate cancer progression. Based on these findings, several therapeutic strategies have been examined in experimental models of chronic pancreatitis as well as pancreatic cancer, in a bid to inhibit/retard PSC activation and thereby alleviate chronic pancreatitis or reduce tumor growth in pancreatic cancer. The challenge that remains is to translate these pre-clinical developments into clinically applicable treatments for patients with chronic pancreatitis and pancreatic cancer.

Therapeutic potential of perineural invasion, hypoxia and desmoplasia in pancreatic cancer

Pancreatic cancer is one of the most fatal human malignancies. Though a relatively rare malignancy, it remains one of the deadliest tumors, with an extremely high mortality rate. The prognosis of patients with pancreatic cancer remains poor; only patients with small tumors and complete resection have a chance of a complete cure. Pancreatic cancer responds poorly to conventional therapies, including chemotherapy and irradiation. Tumor-specific targeted therapy is a relatively recent addition to the arsenal of anti-cancer therapies. It is important to find novel targets to distinguish tumor cells from their normal counterparts in therapeutic approaches. In the past few decades, studies have revealed the molecular mechanisms of pancreatic tumorigenesis, growth, invasion and metastasis. The proteins that participate in the pathophysiological processes of pancreatic cancer might be potential targets for therapy. This review describes the main players in perineural invasion, hypoxia and desmoplasia and the molecular mechanisms of these pathophysiological processes.

Stroma and pancreatic ductal adenocarcinoma: an interaction loop

Pancreatic ductal adenocarcinoma (PDA) has two exceptional features. First, it is a highly lethal disease, with a median survival of less than 6 months and a 5-year survival rate less than 5%. Second, PDA tumor cells are surrounded by an extensive stroma, which accounts for up to 90% of the tumor volume. It is well recognized that stromal microenvironment can accelerate malignant transformation, tumor growth and progression. More importantly, the interaction loop between PDA and its stroma greatly contributes to tumor growth and progression. We propose that the extensive stroma of PDA is closely linked to its poor prognosis. An improved understanding of the mechanisms that contribute to pancreatic tumor growth and progression is therefore urgently needed. Targeting the stroma may thus provide novel prevention, earlier detection and therapeutic options to this deadly malignancy. Accordingly, in this review, we will summarize the mechanism of PDA stroma formation, the role of the stroma in tumor progression and therapy resistance and the potential of stroma-targeted therapeutics strategies.

Dangerous liaisons: pancreatic stellate cells and pancreatic cancer cells

One of the characteristic features of the majority of pancreatic ductal adenocarcinomas is an abundant desmoplastic/stromal reaction. Until recently, this stroma had received little attention from researchers studying the pathogenesis of pancreatic cancer, with most of the research focus resting on the biology of tumor cells themselves. However, evidence is now accumulating that the stroma plays a critical role in pancreatic cancer progression. The cells responsible for producing the stromal reaction in pancreatic cancer are activated pancreatic stellate cells (PSCs, the key effector cells in pancreatic fibrogenesis). In vitro and in vivo studies have convincingly demonstrated a close bi-directional interaction between PSCs and pancreatic cancer cells, which facilitates local tumor growth as well as distant metastasis. PSCs also interact closely with endothelial cells to stimulate angiogenesis and are possibly involved in the known resistance of pancreatic cancer to chemotherapy and radiation. Most interestingly, it has recently been shown that PSCs from the primary tumor can travel to distant metastatic sites where they likely facilitate the seeding, survival, and proliferation of cancer cells. Thus, it is now recognized that the stroma is an important alternative therapeutic target in this disease and concerted pre-clinical research is underway to develop strategies to modulate/deplete the stromal reaction to inhibit cancer progression. The challenge is to translate these developments into clinically applicable treatments for patients.

Pancreatic cancer cell lines can induce prostaglandin e2 production from human blood mononuclear cells

Accumulating evidence suggests an important role for cyclooxygenase-2 (COX-2) in the pathogenesis of a wide range of malignancies. The protumorigenic properties of COX-2 are generally thought to be mediated by its product, PGE(2), which is shown to promote tumor spread and growth by multiple mechanisms but most importantly through modulation of the local immune response in the tumor. Pancreatic tumor cells produce various amounts of PGE(2), some of them being even deficient in COX enzymes or other PGE(2) synthases. Here we describe that, beside pancreatic tumor cells or stromal fibroblasts, human peripheral blood mononuclear cells can also produce PGE(2) upon coculture with pancreatic cancer cells. Stimulating of cellular cPLA2 within PBMCs by secreted factors, presumably sPLA2, from tumor cells appeared crucial, while the direct contact between PBMCs and PDACs seemed to be dispensable for this effect. Our data is emphasizing the complex interactions participating in the formation of the tolerogenic immune milieu within pancreatic tumors.

Pancreatic cancer: the role of pancreatic stellate cells in tumor progression

Pancreatic ductal adenocarcinoma is an aggressive and highly lethal disease frequently characterized by a dense stromal or desmoplastic response. Accumulating evidence exists that tumor desmoplasia plays a central role in disease progression and that e.g. activated pancreatic stellate cells (PSCs) are responsible for the excess matrix production. The mechanisms underlying the tumor versus stroma interplay are complex. Pancreatic cancer cells release mitogenic and fibrogenic stimulants, such as transforming growth factor β(1), platelet-derived growth factor (PDGF), sonic hedgehog, galectin 3, endothelin 1 and serine protease inhibitor nexin 2, all of which may promote the activated PSC phenotype. Stellate cells in turn secrete various factors, including PDGF, stromal-derived factor 1, epidermal growth factor, insulin-like growth factor 1, fibroblast growth factor, secreted protein acidic and rich in cysteine, matrix metalloproteinases, small leucine-rich proteoglycans, periostin and collagen type I that mediate effects on tumor growth, invasion, metastasis and resistance to chemotherapy. This review intends to shed light on the mechanisms by which PSCs in the stroma influence pancreatic cancer development. The increased understanding of this interaction will be of potential value in designing new modalities of targeted therapy. and IAP.

Mechanisms of pancreatic fibrosis and applications to the treatment of chronic pancreatitis

Pancreatic stellate cells (PSCs) play a crucial role in pancreatic fibrogenesis in chronic pancreatitis and in the desmoplastic reaction of pancreatic cancer. When PSCs are stimulated by oxidative stress, ethanol and its metabolite acetaldehyde, and cytokines, the phenotype of quiescent fat-storing cells converts to myofibroblastlike activated PSCs, which then produce extracellular matrix, adhesion molecules, and various chemokines in response to cytokines and growth factors. Recent data suggest that PSCs have a phagocytic function. Plateletderived growth factor is a potent stimulator of PSC proliferation. Transforming growth factor beta, activin A, and connective tissue growth factor also play a role in PSC-mediated pancreatic fibrogenesis through autocrine and paracrine loops. Following pancreatic damage, pathophysiological processes that occur in the pancreas, including pancreas tissue pressure, hyperglycemia, intracellular reactive oxygen species production, activation of protease-activated receptor 2, induction of cyclooxygenase 2, and bacterial infection play a role in sustaining pancreatic fibrosis through increased PSC proliferation and collagen production by PSCs. Targeting PSCs might be an effective therapeutic approach in chronic pancreatitis. Various substances including vitamin A, vitamin E, polyphenols, peroxisome proliferator-activated receptor gamma ligands, and inhibitors of the renin-angiotensin system show great promise of being useful in the treatment of chronic pancreatitis.

Relationship between pancreatic stellate cells and pancreatic cancer

Pancreatic carcinoma is a highly malignant tumor in digestive tract, characterized by rapid progression, early metastasis, limited response to chemotherapy and radiotherapy, and an intense fibrotic reaction known as tumor desmoplasia. Carcinoma cells are surrounded by dense stroma consisting of myofibroblast-like cells, collagens, and fibronectin. Recent studies suggest that pancreatic stellate cells play an important role in this reaction and can stimulate pancreatic tumor cell proliferation, progression and metastasis. This review describes the discovery, activation pathway, interaction between pancreatic stellate cells and pancreatic tumor cells, and the role of pancreatic stellate cells in the process of pancreatic cancer initiation, progression, and metastasis.

The pancreatic stellate cell: a star on the rise in pancreatic diseases

Pancreatic stellate cells (PaSCs) are myofibroblast-like cells found in the areas of the pancreas that have exocrine function. PaSCs are regulated by autocrine and paracrine stimuli and share many features with their hepatic counterparts, studies of which have helped further our understanding of PaSC biology. Activation of PaSCs induces them to proliferate, to migrate to sites of tissue damage, to contract and possibly phagocytose, and to synthesize ECM components to promote tissue repair. Sustained activation of PaSCs has an increasingly appreciated role in the fibrosis that is associated with chronic pancreatitis and with pancreatic cancer. Therefore, understanding the biology of PaSCs offers potential therapeutic targets for the treatment and prevention of these diseases.

Resveratrol interferes with AKT activity and triggers apoptosis in human uterine cancer cells

Background

Endometrial cancer is the fourth most prominent cancer among all feminine cancers in the Western world. Resveratrol, a natural anti-oxidant found in red wine emerging as a novel anticancer agent, exerts antiproliferative and pro-apoptotic activity in various cancer cell types, but its effect on uterine cancer cells is poorly understood. At the molecular level, resveratrol has been reported to inhibit cyclooxygenase (COX) expression and/or activity; in endometrial cancer cells, COX-2 is overexpressed and confers cellular resistance to apoptosis. The aim of the present study was to determine if resveratrol could exert anti-proliferative and pro-apoptotic activity over uterine cancer cells upon inhibition of COX-2 expression and/or activity. Six different human uterine cancer cell lines were used as a model (HeLa, Hec-1A, KLE, RL95-2, Ishikawa and EN-1078D).

Results and discussion

High-dose of resveratrol triggered apoptosis in five out of six uterine cancer cell lines, as judged from Hoechst nuclear staining and effector caspase cleavage. In accordance, uterine cancer cell proliferation was decreased. Resveratrol also reduced cellular levels of the phosphorylated/active form of anti-apoptotic kinase AKT. Endogenous COX-2 protein levels were decreased, concomitant with a decrease in production of COX metabolites PGE2 and PGF2α, in each uterine cancer cell line expressing detectable levels of COX-1 and/or COX-2 in presence of resveratrol. Although COX expression was identified as a target of resveratrol in uterine cancer cells, inhibition of COX activity or exogenously added PGE2 did not modulate the effect of resveratrol on cellular proliferation.

Conclusion

High-dose of resveratrol exerts tumoricidal activity over uterine cancer cells and regulates COX expression. In these cells, resveratrol would not directly target COX activity, but possibly other enzymes involved in prostaglandin synthesis that act downstream of the COXs.

Pancreatic stellate cells: new kids become mature

Vitamin A and its metabolites can reverse activation of culture activated pancreatic stellate cells and prevent ethanol induced pancreatic stellate cell activation

Activation of focal adhesion kinase enhances the adhesion and invasion of pancreatic cancer cells via extracellular signal-regulated kinase-1/2 signaling pathway activation

Background

Interaction with integrin and focal adhesion kinase (FAK) regulates the cancer cell adhesion and invasion into extracellular matrix (ECM). In addition, phosphorylation of FAK correlates with the increase of cell motility and invasion. Adhesion and spreading of cancer cells on a variety of ECM proteins, including collagen type IV (Coll IV), leads to an increase in tyrosine phosphorylation and activation of FAK. In this study, we investigated the mechanism of activation of FAK and its downstream extracellular signal-regulated kinase (ERK)-1/2 signaling following stimulation by interleukin (IL)-1α and adhesion to ECM with subsequent enhancement of pancreatic cancer cell adhesion and invasion.

Results

In immunoblotting analysis, all three pancreatic cancer cell lines (AsPC-1, BxPC-3, and Capan-2) expressed the protein of FAK and β₁ integrin. Enhancement of FAK protein association with β₁ integrin when cells were plated on Coll IV was more increased by stimulation with IL-1α. Preincubation with anti-β₁ integrin antibody and FAK siRNA transfection inhibited the association of FAK with β₁ integrin of pancreatic cancer cells. FAK phosphorylation was observed by adhesion to Coll IV, furthermore, stronger FAK phosphorylation was observed by stimulation with IL-1α of pancreatic cancer cells adhered to Coll IV in time-dependent manner. Genistein, a tyrosine kinase inhibitor, markedly inhibited the FAK phosphorylation. IL-1α stimulation and Coll IV adhesion enhanced the activation of Ras, as evidenced by the increased Ras-GTP levels in pancreatic cancer cells. Activation of Ras correlated with the phosphorylation of ERK. While not statistical affecting the apoptosis of pancreatic cancer cells, IL-1α-induced adhesion and invasion on Coll IV were inhibited with FAK gene silencing by siRNA, β₁ integrin blocking, and inhibition of FAK phosphorylation. PD98059, a MEK inhibitor, also inhibited IL-1α-induced enhancement of adhesion and invasion in pancreatic cancer cells.

Conclusion

Our results demonstrated that activation of FAK is involved with the aggressive capability in pancreatic cancer through Ras/ERK signaling pathway. Based on our results, we suggest that the modification of IL-1, FAK, and integrins functions might be a novel therapeutic approach to aggressive spread of pancreatic cancer.