Characterization of keratinocyte growth factor and receptor expression in human pancreatic cancer

Plasma Levels of Keratinocyte Growth Factor Are Significantly Elevated for 5 Weeks After Minimally Invasive Colorectal Resection Which May Promote Cancer Recurrence and Metastasis

Background: Human Keratinocyte Growth Factor (KGF) is an FGF family protein produced by mesenchymal cells. KGF promotes epithelial cell proliferation, plays a role in wound healing and may also support tumor growth. It is expressed by some colorectal cancers (CRC). Surgery's impact on KGF levels is unknown. This study's purpose was to assess plasma KGF levels before and after minimally invasive colorectal resection (MICR) for CRC. Aim: To determine plasma KGF levels before and after minimally invasive colorectal resection surgery for cancer pathology. Method: CRC MICR patients (pts) in an IRB approved data/plasma bank were studied. Pre-operative (pre-op) and post-operative (post-op) plasma samples were taken/stored. Late samples were bundled into 7 day blocks and considered as single time points. KGF levels (pg/ml) were measured via ELISA (mean ± SD). The Wilcoxon paired t-test was used for statistical analysis. Results: Eighty MICR CRC patients (colon 61%; rectal 39%; mean age 65.8 ± 13.3) were studied. The mean incision length was 8.37 ± 3.9 and mean LOS 6.5 ± 2.6 days. The cancer stage breakdown was; I (23), II (26), III (27), and IV (4). The median pre-op KGF level was 17.1 (95 %CI: 14.6-19.4; n = 80); significantly elevated (p < 0.05) median levels (pg/ml) were noted on post-op day (POD) 1 (23.4 pg/ml; 95% CI: 21.4-25.9; n = 80), POD 3 (22.5 pg/ml; 95% CI: 20.7-25.9; n = 76), POD 7-13 (21.8 pg/ml; 95% CI: 17.7-25.4; n = 50), POD 14-20 (20.1 pg/ml; 95% CI: 17.1-23.9; n = 33), POD 21-27 (19.6 pg/ml; 95% CI: 15.2-24.9; n = 15) and on POD 28-34 (16.7 pg/ml; 95% CI: 14.0-25.8; n = 12). Conclusion: Plasma KGF levels were significantly elevated for 5 weeks after MICR for CRC. The etiology of these changes is unclear, surgical trauma related acute inflammatory response and wound healing process may play a role. These changes, may stimulate angiogenesis in residual tumor deposits after surgery.

Integrated Analysis of Structural Variation and RNA Expression of FGFR2 and Its Splicing Modulator ESRP1 Highlight the ESRP1amp-FGFR2norm-FGFR2-IIIchigh Axis in Diffuse Gastric Cancer

Gastric Cancer (GC) is one of the most common and deadliest types of cancer in the world. To improve GC prognosis, increasing efforts are being made to develop new targeted therapies. Although FGFR2 genetic amplification and protein overexpression in GC have been targeted in clinical trials, so far no improvement in patient overall survival has been found. To address this issue, we studied genetic and epigenetic events affecting FGFR2 and its splicing regulator ESRP1 in GC that could be used as new therapeutic targets or predictive biomarkers. We performed copy number variation (CNV), DNA methylation, and RNA expression analyses of FGFR2/ESRP1 across several cohorts. We discovered that both genes were frequently amplified and demethylated in GC, resulting in increased ESRP1 expression and of a specific FGFR2 isoform: FGFR2-IIIb. We also showed that ESRP1 amplification in GC correlated with a significant decreased expression of FGFR2-IIIc, an alternative FGFR2 splicing isoform. Furthermore, when we performed a survival analysis, we observed that patients harboring diffuse-type tumors with low FGFR2-IIIc expression revealed a better overall survival than patients with FGFR2-IIIc high-expressing diffuse tumors. Our results encourage further studies on the role of ESRP1 in GC and support FGFR2-IIIc as a relevant biomarker in GC.

Cultured Epidermal Melanocyte Transplantation in Vitiligo: A Review Article

BACKGROUND

The color of the skin is highly heritable but can be influenced by the environments and endocrine factors. Many other factors, sometimes destructive, are also involved in the formation of skin color, which sometimes affects pigmentation patterns. Vitiligo is an autoimmune hypopigmentation painless disorder with appearance of white patches and psychological effects on patients. It is a disease in which melanocytes of the skin are destroyed in certain areas; therefore depigmentation appears.

METHODS

We studied more than 60 articles. Several therapeutic methods have been used to return the color of skin in vitiligo. These methods include non-invasive treatment and surgical techniques. Among all these therapies, cell transplantation is an advanced procedure in regenerative medicine. Extraction of melanocytes from normal skin and then their cultivation in the laboratory provides a large number of these cells, the transplanting of which to depigmentation areas stimulates the site to irreversibly produce melanin.

RESULTS

The transplantation methods of these cells have been evolved over many years and the methods of producing blister have been changed to the injection of these cells to the target sites.

CONCLUSION

In this review, autologous cultured melanocyte transplantation has been considered to be the most viable, safe, and effective method in the history of vitiligo treatments.

Emerging Roles of Fibroblast Growth Factor 10 in Cancer

Whilst cross-talk between stroma and epithelium is critical for tissue development and homeostasis, aberrant paracrine stimulation can result in neoplastic transformation. Chronic stimulation of epithelial cells with paracrine Fibroblast Growth Factor 10 (FGF10) has been implicated in multiple cancers, including breast, prostate and pancreatic ductal adenocarcinoma. Here, we examine the mechanisms underlying FGF10-induced tumourigenesis and explore novel approaches to target FGF10 signaling in cancer.

Cancer stem cells and epithelial-mesenchymal transition: Novel therapeutic targets for cancer

Despite the development of various therapeutic approaches, recurrence and metastasis remain major problems for patients with advanced cancer. Recent studies have shown that cancer stem cells (CSCs) play an important role in cancer aggressiveness. In cancer tissues, a small number of CSCs are able to self-renew and differentiate into heterogeneous cancer cells. CSCs usually remain in the resting phase of the cell cycle and possess efficient drug efflux pathways. Thus, they are resistant to chemoradiotherapy and surviving CSCs contribute to recurrence. During cancer metastasis, CSCs undergo epithelial-mesenchymal transition (EMT), thereby acquiring mesenchymal features, migrating to adjacent stromal tissues, and invading blood or lymph vessels. Recent studies showed that EMT-inducible factors also enhance or induce CSC-like features in cancer cells. These findings suggest that EMT is closely correlated with cancer recurrence and metastasis. Inhibition of nestin, a CSC marker, reduces the aggressiveness of several types of cancer. Suppression of the mesenchymal variant of fibroblast growth factor (FGFR)-2, FGFR-2 IIIc, and regulation of the EMT using epithelial splicing regulatory protein 1 (ESRP1) are effective in the treatment of immunodeficient mice with pancreatic cancer. The roles of CSCs and EMT in cancer and possible therapies are discussed in this review.

Role of fibroblast growth factors in pancreatic cancer

Fibroblast growth factors belong to a family of growth factors that are involved in various processes in organism and have a wide range of biological functions. Specifically for pancreas, FGFs are important during both organogenesis and carcinogenesis. One of the main characteristic of pancreatic cancer, is it close interaction between cancer and stromal cells via different factors, including FGF. Pathological changes in FGF/FGFR signaling pathway is a complex process. The remodeling effects and stimulation of tumor growth are mostly depend not only on types of receptors, but also from their isoforms. FGF/FGFR signaling pathway is a perspective specific marker for cancer progression, and a potential drug target, which can be used for treatment of pancreatic cancer.

Clinicopathological correlation of keratinocyte growth factor and matrix metalloproteinase-9 expression in human gastric cancer

AIMS AND BACKGROUND

Keratinocyte growth factor (KGF) is reported to be implicated in the growth of some cancer cells. Matrix metalloproteinase 9 (MMP-9) is thought to enhance the tumor invasion and metastasis ability. This study was aimed at analyzing the relationship between KGF and MMP-9 expression and patients' clinicopathological characteristics to clarify the clinical significance of the expression of KGF and MMP-9 in gastric cancer.

METHODS

Tissue samples from 161 patients with primary gastric cancer were investigated using immunohistochemistry. The relationship between KGF and/or MMP-9 expression and clinicopathological characteristics was analyzed.

RESULTS

KGF expression and MMP-9 expression in gastric cancer tissue were observed in 62 cases (38.5%) and 97 cases (60.2%), respectively. MMP-9 was significantly associated with depth of invasion, lymph node metastasis and TNM stage. The prognosis of MMP-9-positive patients was significantly poorer than that of MMP-9-negative patients (p = 0.009). KGF expression was positively correlated with MMP-9 expression in gastric cancer, and the prognosis of patients with both KGF- and MMP-9-positive tumors was significantly worse than that of patients with negative tumors for either factor (p = 0.045). Expression of MMP-9 was revealed to be an independent prognostic factor (p = 0.026).

CONCLUSIONS

Coexpression of KGF and MMP-9 in gastric cancer could be a useful prognostic factor, and MMP-9 might also serve as a novel target for both prognostic prediction and therapeutics.

Keratinocyte growth factor receptor: a therapeutic target in solid cancer

INTRODUCTION

The treatment effects of advanced solid cancer are unsatisfactory, and novel therapeutic approaches are much needed. Keratinocyte growth factor receptor (KGFR) is a receptor tyrosine kinase that is primarily localized on epithelial cells. KGFR may play important roles in epithelial cell proliferation and differentiation, epithelial wound repair, embryonic development, immunity, tumor formation and development.

AREAS COVERED

This review summarizes the expression, function and mechanism of KGFR in solid cancer, and analyzes its value for the cancer therapy. Furthermore, this study discusses the limitations of KGFR-based therapy, and envisages future developments in the clinical applications of KGFR.

EXPERT OPINION

KGFR may function as an ideal therapeutic target for solid cancer. Continued basic investigation of KGFR-mediated pathways will push insight into the novel strategies of target therapy. More in vivo studies and clinical trials should be performed to promote the translational bridging of the latest research into clinical application.

Keratinocyte Growth Factor Gene Electroporation into Skeletal Muscle as a Novel Gene Therapeutic Approach for Elastase-Induced Pulmonary Emphysema in Mice

Pulmonary emphysema is a progressive disease with airspace destruction and an effective therapy is needed. Keratinocyte growth factor (KGF) promotes pulmonary epithelial proliferation and has the potential to induce lung regeneration. The aim of this study was to determine the possibility of using KGF gene therapy for treatment of a mouse emphysema model induced by porcine pancreatic elastase (PPE). Eight-week-old BALB/c male mice treated with intra-tracheal PPE administration were transfected with 80 μg of a recombinant human KGF (rhKGF)-expressing FLAG-CMV14 plasmid (pKGF-FLAG gene), or with the pFLAG gene expressing plasmid as a control, into the quadriceps muscle by electroporation. In the lung, the expression of proliferating cell nuclear antigen (PCNA) was augmented, and surfactant protein A (SP-A) and KGF receptor (KGFR) were co-expressed in PCNA-positive cells. Moreover, endogenous KGF and KGFR gene expression increased significantly by pKGF-FLAG gene transfection. Arterial blood gas analysis revealed that the PaO₂ level was not significantly reduced on day 14 after PPE instillation with pKGF-FLAG gene transfection compared to that of normal mice. These results indicated that KGF gene therapy with electroporation stimulated lung epithelial proliferation and protected depression of pulmonary function in a mouse emphysema model, suggesting a possible method of treating pulmonary emphysema.

Potential prognostic and diagnostic application of a novel monoclonal antibody against keratinocyte growth factor receptor

KGFR is involved in the pathogenesis of several human cancers. In this study, we generated and characterized a monoclonal antibody specific to KGFR (SC-101 mAb) and evaluated its potential use in basic research and as a diagnostic and prognostic tool. The specificity and biological activity of the SC-101 mAb were evaluated by Western blotting, immunofluorescence, and immunoprecipitation analyses on various cell lines. KGFR expression in breast, pancreatic, and thyroid carcinoma was assessed by immunohistochemistry (IHC) with SC-101 mAb. KGFR expression levels revealed by SC-101 mAb resulted to increase proportionally with tumor grade in breast and pancreatic cancer. In addition, SC-101 mAb was able to detect KGFR down-modulation in thyroid cancer. SC-101 mAb might represent a useful tool for basic research applications, and it could also contribute to improve the accuracy of diagnosis and prognosis of epithelial tumors.

Inhibition of fibroblast growth factor receptor 2 attenuates proliferation and invasion of pancreatic cancer

The alternative splicing of the extracellular domain of fibroblast growth factor receptor (FGFR)-2 generates the IIIb and IIIc isoforms. Expression of FGFR-2 IIIb correlates with vascular endothelial growth factor-A (VEGF-A) expression and venous invasion of pancreatic ductal adenocarcinoma (PDAC). By contrast, FGFR-2 IIIc expression correlates with faster development of liver metastasis after surgery, and increased proliferation rates and invasion of the cancer. In this study, we analyzed the expression and roles of total FGFR-2 (both isoforms) to determine the effectiveness of FGFR-2-targeting therapy for PDAC. Immunohistochemically, FGFR-2 was highly expressed in 25/48 (52.1%) PDAC cases, and correlated with advanced stage cancer. In FISH analysis, FGFR2 was amplified in 3/7 PDAC cell lines. We stably transfected an FGFR-2 shRNA targeting the IIIb and IIIc isoforms into FGFR2-amplified PDAC cells. The proliferation rates, migration, and invasion of FGFR-2-shRNA-transfected cells were lower than those of control cells in vitro. In response to FGF-2, FGFR-2-shRNA-transfected cells showed decreased phosphorylation of ERK compared with control cells. The FGFR-2-shRNA-transfected cells also expressed lower levels of vascular endothelial growth factor-A than control cells, and formed smaller s.c. tumors in nude mice. These findings suggest that FGFR-2 is a therapeutic target for inhibition in PDAC.

Lumican as a novel marker for differential diagnosis of Bowen disease and actinic keratosis

Lumican, a member of the small leucine-rich proteoglycan family, regulates the assembly and diameter of collagen fibers in the extracellular matrix of various tissues. Lumican expression correlates with pathological conditions, including skin fragility, corneal opacification, and corneal and cardiac wound healing. Lumican is overexpressed in tumor cells, including in the breast, colorectal, neuroendocrine cell, uterine cervical, and pancreatic cancers. Lumican expression also correlates with the growth and metastasis of various malignancies. For example, lumican expression is lower in the dermis of malignant melanoma cases than in early-stage melanomas. However, the expression patterns and roles of lumican in nonmelanoma skin cancer have not been elucidated. In this study, we used immunohistochemistry and in situ hybridization to examine the expression patterns of lumican in normal skin, Bowen disease, and actinic keratosis. In normal skin, lumican was expressed in the collagen fibers in the dermis, acrosyringium, follicular epithelium, and sebocytes but not in epidermal keratinocytes. In Bowen disease, lumican was expressed in 34 (91.8%) of 37 patients. Notably, all cases of actinic keratosis were negative for lumican. These findings suggest that lumican plays an important role in the pathogenesis of Bowen disease and actinic keratosis and might be useful as an adjunct to the diagnosis for subtypes of 2 diseases: bowenoid actinic keratosis and Bowen disease in sun-exposed areas.

Epithelial splicing regulatory protein 1 is a favorable prognostic factor in pancreatic cancer that attenuates pancreatic metastases

Epithelial splicing regulatory protein 1 (ESRP1) binds the FGFR-2 auxiliary cis-element ISE/ISS-3, located in the intron between exon IIIb and IIIc, and primarily promotes FGFR-2 IIIb expression. Here we assessed the role of ESRP1 in pancreatic ductal adenocarcinoma (PDAC). Immunohistochemical analysis was performed using anti-ESRP1, FGFR-2 IIIb and FGFR-2 IIIc antibodies in 123 PDAC cases. ESRP1-expression vector and small interference RNA (siRNA) targeting ESRP1 were transfected into human PDAC cells, and cell growth, migration and invasion were analyzed. In vivo heterotopic and orthotopic implantations using ESRP1 overexpression clones were performed and effects on pancreatic tumor volumes and hepatic and pulmonary metastases determined. ESRP1 immunoreactivity was strong in the nuclei of cancer cells in well-to-moderately differentiated PDACs, but weak in poorly-differentiated cancers. Well-to-moderately differentiated cancers also exhibited high FGFR-2 IIIb and low FGFR-2 IIIc expression, whereas this ratio was reversed in the poorly-differentiated cancers. Increased ESRP1 expression was associated with longer survival by comparison with low-ESRP1 expression, and PANC-1 cells engineered to express ESRP1 exhibited increased FGFR-2 IIIb expression and decreased migration and invasion in vitro, whereas ESRP1 siRNA-transfected KLM-1 cells exhibited increased FGFR-2 IIIc expression and increased cell growth, migration and invasion. In vivo, ESRP1-overexpressing clones formed significantly fewer liver metastases as compared with control clones. ESRP1 regulates the expression pattern of FGFR-2 isoforms, attenuates cell growth, migration, invasion, and metastasis, and is a favorable prognostic factor in PDAC. Therefore, devising mechanisms to up-regulate ESRP1 may exert a beneficial therapeutic effect in PDAC.

Clinicopathological significance of expression of keratinocyte growth factor protein in pancreatic ductal adenocarcinoma

AIM: To assess the clinicopathological significance of expression of keratinocyte growth factor (KGF) protein in pancreatic ductal adenocarcinoma (PDAC).

METHODS: The expression of KGF protein in 51 paraffin-embedded PDAC specimens and matched tumor-adjacent pancreatic tissue specimens was detected by immunohistochemistry. The relationship between KGF protein expression and clinicopathological characteristics of PDAC was analyzed.

RESULTS: The expression of KGF protein was significantly higher in PDAC than in matched non-cancerous pancreatic tissues (Z = -4.766, P < 0.001). The expression of KGF protein was positively correlated with hepatic metastasis (χ² = 4.113, P < 0.05). Mean survival time was shorter in KGF (+) patients than in KGF (-) ones (384 d vs 621 d).

CONCLUSION: Expression of KGF is up-regulated in PDAC. KGF up-regulation may be related with hepatic metastasis of PDAC. Mean survival time is shorter in KGF (+) patients than in KGF (-) ones.

The heparin-binding protein interactome in pancreatic diseases

BACKGROUND

The cellular microenvironment plays an important role in the regulation of homoeostasis and is a source of potential biomarkers and drug targets. In a genome-wide analysis the extracellular proteins that bind to heparin (HBPs) have been shown to form highly modular and interconnected extracellular protein regulatory networks. Using a systems biology approach, we have investigated the role of HBP networks in the normal pancreas and pancreatic digestive diseases.

METHODS

Lists of mRNAs encoding for HBPs associated with the normal pancreas (NP), acute pancreatitis (AP), chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC) were obtained using public databases and publications. Networks of the putative protein interactomes derived from mRNA expression data of HBPs were built and analysed using cluster analysis, gene ontology term enrichment and canonical pathways analysis.

RESULTS

The extracellular heparin-binding putative protein interactomes in the pancreas were better connected than their non heparin-binding counterparts, having higher clustering coefficients in the normal pancreas (0.273), acute pancreatitis (0.457), chronic pancreatitis (0.329) and pancreatic ductal adenocarcinoma (0.269). 'Hepatic Fibrosis/Hepatic Stellate Cell Activation' appears to be a significant canonical pathway in pancreatic homoeostasis in health and disease with a large number of important HBPs.

CONCLUSIONS

Our analyses clearly demonstrate that HBPs form disease-specific and highly connected networks that can be explored for potential biomarkers and as collective drug targets via the modification of heparin binding properties.

N-cadherin-mediated adhesion and signaling from development to disease: lessons from mice

Of the 20 classical cadherin subtypes identified in mammals, the functions of the two initially identified family members E- (epithelial) and N- (neural) cadherin have been most extensively studied. E- and N-Cadherin have mostly mutually exclusive expression patterns, with E-cadherin expressed primarily in epithelial cells, whereas N-cadherin is found in a variety of cells, including neural, muscle, and mesenchymal cells. N-Cadherin function, in particular, appears to be cell context-dependent, as it can mediate strong cell-cell adhesion in the heart but induces changes in cell behavior in favor of a migratory phenotype in the context of epithelial-mesenchymal transition (EMT). The ability of tumor cells to alter their cadherin expression profile, for example, E- to N-cadherin, is critical for malignant progression. Recent advances in mouse molecular genetics, and specifically tissue-specific knockout and knockin alleles of N-cadherin, have provided some unexpected results. This chapter highlights some of the genetic studies that explored the complex role of N-cadherin in embryonic development and disease.

MUC4 potentiates invasion and metastasis of pancreatic cancer cells through stabilization of fibroblast growth factor receptor 1

MUC4 is a type-1 transmembrane mucin differentially expressed in multiple cancers and has previously been shown to potentiate progression and metastasis of pancreatic cancer. In this study, we investigated the molecular mechanisms associated with the MUC4-induced invasion and metastasis in pancreatic cancer. Stable silencing of MUC4 in multiple pancreatic cancer cells resulted in the downregulation of N-cadherin and its interacting partner fibroblast growth factor receptor 1 (FGFR1) through downregulation of partly by pFAK, pMKK7, pJNK and pc-Jun pathway and partly through PI-3K/Akt pathway. The downregulation of FGFR1 in turn led to downregulation of pAkt, pERK1/2, pNF-κB, pIkBα, uPA, MMP-9, vimentin, N-cadherin, Twist, Slug and Zeb1 and upregulation of E-cadherin, Occludin, Cytokeratin-18 and Caspase-9 in MUC4 knockdown BXPC3 and Capan1 cells compared with scramble vector transfected cells. Further, downregulation of FGFR1 was associated with a significant change in morphology and reorganization of the actin-cytoskeleton, leading to a significant decrease in motility (P < 0.00001) and invasion (P < 0.0001) in vitro and decreased tumorigenicity and incidence of metastasis in vivo upon orthotopic implantation in the athymic mice. Taken together, the results of the present study suggest that MUC4 promotes invasion and metastasis by FGFR1 stabilization through the N-cadherin upregulation.

Analysis of pancreatic cancer microenvironment: role of macrophage infiltrates and growth factors expression

Background: Research over the last twenty years has yielded much insight into pancreatic cancer biology, but it has neither improved diagnostics methods nor the way of treatment. The question remains as to what the critical deciding factor is in making pancreatic cancer such an aggressive disease.

Methods: Pancreatic tumor tissue came from 36 patients. To assess lymphatic vessels color lymphangiography and immunohistochemistry were used. Activity of matrix metalloproteinases was studied with gel and in situ zymography. Expression of growth factors and infiltrating immune cells were investigated using immunohistochemistry.

Results: Our study revealed that the structures that correspond to lymphatic vessels were not observed in tumor center but only at the edge of the tumor. All studied growth factors were present in tumor tissue. We found that the difference in expression between G2 and G3 stage was statistically relevant in cases of c-Met receptor. Inflammatory cells were present around neoplastic glands and also strongly around nerves infiltrated by cancer cells. The number of infiltrating macrophages in tumor tissue was significantly higher in group with metastases to lymph nodes.

Conclusion: We showed two factors that influence pancreatic cancer progression and invasion: c-Met receptors and macrophages infiltrating tumor tissue. Based on our analysis, this indicates that epithelial-mesenchymal transition might be crucial in the progression of pancreatic cancer.

Fibroblast growth factor receptor 2: expression, roles, and potential as a novel molecular target for colorectal cancer

The fibroblast growth factor receptor (FGFR) family consists of four members, named FGFR1, 2, 3, and 4. All 4 FGFRs and their ligands, fibroblast growth factors (FGFs), are expressed in colorectal cancer (CRC). Recent studies have shown that FGFR2 plays important roles in cancer progression; therefore, it is of great interest as a novel target for cancers. Expression of FGFR2 regulates migration, invasion, and growth in CRC. Expression of the FGFR2 isoform FGFR2 IIIb was associated with well-differentiated histological types, and its specific ligand, FGF7, enhanced angiogenesis and adhesion to type-IV collagen via FGFR2 IIIb in CRC. FGFR2 IIIc is detected in CRC, but its roles have not been well elucidated. Interactions between FGFR2 IIIb and IIIc and FGFs may play important roles in CRC via autocrine and/or paracrine signaling. Several kinds of molecular-targeting agents against FGFR2 have been developed; however, it is not clear how a cancer treatment can most effectively inhibit FGFR2 IIIb or FGFR2 IIIc, or both isoforms. The aim of this paper is to summarize the roles of FGFR2 and its isoforms in CRC and clarify whether they are potent therapeutic targets for CRC.

Enhanced expression of fibroblast growth factor receptor 2 IIIc promotes human pancreatic cancer cell proliferation

In pancreatic ductal adenocarcinoma (PDAC), the fibroblast growth factor receptor 1 (FGFR-1) IIIb isoform correlates with the inhibition of cancer cell proliferation, migration, and invasion, whereas FGFR-1 IIIc enhances cancer cell proliferation. The FGFR-2 IIIb isoform is expressed in PDAC, and its expression correlates with increased venous invasion. We examined the role of FGFR-2 IIIc in PDAC. FGFR-2 IIIc was expressed in all six pancreatic cancer cell lines examined and was highest in PANC-1 cells. FGFR-2 IIIc was abundant in the cancer cells from 83 of 117 PDAC cases, which correlated with decreased duration to development of liver metastasis after surgery. FGFR-2 IIIc-transfected cells exhibited increased proliferation in vitro and formed larger subcutaneous and orthotopic tumors, the latter producing more liver metastases. Moreover, FGF-2 exerted a more rapid stimulatory effect on the levels of phosphorylated extracellular signal-regulated kinase (p-ERK) in FGFR-2 IIIc stably transfected PANC-1 cells, compared with control cells. FGFR-2 IIIc-transfected cells also formed more spheres and contained more side population cells. Suppression of FGFR-2 IIIc expression inhibited the proliferation of PANC-1 cells, whereas an anti-FGFR-2 IIIc antibody inhibited the proliferation and migration of PANC-1 cells. Thus, high FGFR-2 IIIc levels in PDAC contribute to disease aggressiveness and confer to pancreatic cancer cells features suggestive of cancer stem cells, indicating that FGFR-2 IIIc may be a novel and important therapeutic target in PDAC.

Keratinocyte growth factor induces matrix metalloproteinase-9 expression and correlates with venous invasion in pancreatic cancer

Keratinocyte growth factor (KGF), also known as fibroblast growth factor-7, and KGF receptor (KGFR) play important roles in the growth of epithelial cells and are overexpressed in a variety of malignant epithelial tumors, including pancreatic ductal adenocarcinoma (PDAC). We previously reported that co-expression of KGF and KGFR in PDAC is associated with venous invasion, enhanced vascular endothelial growth factor A expression and poor prognosis. Matrix metalloproteinase-9 (MMP-9) is known to participate in the degradation of type IV collagen, which is a primary component of extracellular matrices in the vascular basement membrane. In the present study, we examined the expression and roles of KGF, KGFR and MMP-9 in human PDAC cell lines and tissues. Quantitative real-time polymerase chain reaction analysis demonstrated the expression of MMP-9 mRNA in all eight PDAC cell lines. KGF, KGFR and MMP-9 were, respectively, expressed in 27 (43%), 23 (37%) and 35 (56%) of 63 patients. Each expression of KGF, KGFR or MMP-9 correlated positively with venous invasion. Furthermore, expression of KGF or MMP-9 correlated positively with liver metastasis. KGF-positive cases exhibited shorter survival than KGF-negative cases, while KGFR and MMP-9 expression were unrelated to prognosis. Administration of recombinant human KGF increased MMP-9 expression in PDAC cells, while transient transfection with short hairpin RNAs targeting KGF transcripts reduced MMP-9 expression in PDAC cells. Moreover, recombinant human KGF significantly enhanced migration and invasion of PDAC cells. These findings suggest that KGF and KGFR promote venous invasion via MMP-9 in PDAC, and closely correlate with liver metastasis. The KGF/KGFR pathway may be a critical therapeutic target for PDAC metastasis.

Keratinocyte growth factor stimulates growth of MIA PaCa-2 cells through extracellular signal-regulated kinase phosphorylation

Keratinocyte growth factor (KGF), also known as fibroblast growth factor-7, is mainly synthesized by mesenchymal cells. KGF modulates proliferation, differentiation, migration and adhesion to extracellular matrices of epithelial cells that specifically express the KGF receptor (KGFR). We previously reported that KGF is expressed in cancer cells and adjacent stromal fibroblasts in human pancreatic cancer tissues. Furthermore, KGF is thought to stimulate the growth of certain pancreatic cancer cell lines. The aim of the present study was to examine whether the mitogen-activated protein kinase (MAPK) pathway contributes to exogenous KGF-induced pancreatic cancer cell growth. Recombinant human KGF (rhKGF) was administered to MIA PaCa-2 cells, which expressed KGFR and negligible levels of KGF. Cell growth rates in MIA PaCa-2 cells were significantly increased in a dose-dependent manner following the addition of rhKGF. In the MAPK pathway, phosphorylation of extracellular signal-regulated kinase (ERK) in MIA PaCa-2 cells was increased in a dose-dependent manner, and phosphorylation of p38 was slightly increased following the administration of 100 ng/ml rhKGF. In contrast, JNK was not phosphorylated following the addition of rhKGF in MIA PaCa-2 cells. U0126, a specific inhibitor of ERK activation, decreased the rhKGF-induced phosphorylation of ERK and the growth rates of MIA PaCa-2 cells. These findings indicated that phosphorylation of the ERK signaling pathway plays a significant role in exogenous KGF-induced pancreatic cancer cell growth.

Monoclonal antibodies to fibroblast growth factor receptor 2 effectively inhibit growth of gastric tumor xenografts

PURPOSE

Overexpression of fibroblast growth factor receptor 2 (FGFR2) may be a causative factor of a number of human tumors, especially gastric tumors of the poorly differentiated type. We investigated whether monoclonal antibodies (mAbs) directed against FGFR2 can inhibit the growth of tumors in xenograft models.

EXPERIMENTAL DESIGN

We generated and characterized 3 mAbs that recognize different epitopes on FGFR2: GAL-FR21, GAL-FR22, and GAL-FR23. The ability of the mAbs to recognize the FGFR2IIIb and FGFR2IIIc isoforms of FGFR2 was determined, as was their ability to block binding of FGF ligands to FGFR2. The capability of the mAbs to inhibit FGF-induced FGFR2 phosphorylation and to downmodulate FGFR2 expression was also investigated. Finally, the ability of the anti-FGFR2 mAbs to inhibit tumor growth was determined by establishing xenografts of SNU-16 and OCUM-2M human gastric tumor cell lines in nude mice, treating with each mAb (0.5-5 mg/kg intraperitoneally twice weekly) and monitoring tumor size.

RESULTS

Of the 3 mAbs, GAL-FR21 binds only the FGFR2IIIb isoform, whereas GAL-FR22 and GAL-FR23 bind to both the FGFR2IIIb and FGFR2IIIc forms, with binding regions respectively in the D3, D2-D3, and D1 domains of FGFR2. GAL-FR21 and GAL-FR22 blocked the binding of FGF2, FGF7 and FGF10 to FGFR2IIIb. GAL-FR21 inhibited FGF2 and FGF7 induced phosphorylation of FGFR2, and both mAbs downmodulated FGFR2 expression on SNU-16 cells. These mAbs effectively inhibited growth of established SNU-16 and OCUM-2M xenografts in mice.

CONCLUSIONS

Anti-FGFR2 mAbs GAL-FR21 and GAL-FR22 have potential for the treatment of gastric and other tumors.

Combined treatment with cytoprotective agents and radiotherapy

Radiotherapy is associated with several toxicities affecting healthy tissues. One of the strategies aimed at decreasing radiation toxicity is the use of radioprotective agents, such as amifostine and palifermin, or factors stimulating hemopoetic stem cells (colony stimulating factors, CSFs): granulocyte-CSF, granulocyte macrophage-CSF and recombinant erythropoetins. The potential beneficial effect of these substances demonstrated in preclinical in vitro and in vivo studies led to numerous clinical trials. This review addresses the current experience on the use of cytoprotective agents in combination with radiotherapy, with particular focus on the safety of these approaches. Despite a relatively large body of literature data, the role of cytoprotective agents combined with radiotherapy remains controversial. Overall, their use in this application is still limited due to modest radioprotective effect for normal tissues, potential risk of tumor protection and increased treatment toxicity. The use of erythropoetins in combination with radiotherapy should generally be discouraged, whereas the safe and effective application of other agents warrants further investigations.

Chronic pancreatitis and pancreatic cancer: prediction and mechanism

We investigated the SPINK 1 mutations in 156 sporadic pancreatic cancer (PCa), and 8 pancreatic cancer with chronic pancreatitis (CPPCa) patients, and in 527 healthy subjects. The results demonstrated that 3 of 8 patients with CPPCa (37.5%) had the SPINK 1 gene N34S mutation. In addition, 3 of 156 sporadic PCa patients (1.9%) and 1 of them (0.6%) had the N34S and IVS3+2T>C mutation, respectively. The combined frequency of 2.5% was significantly higher than that of healthy subjects (0.38%), suggesting that the SPINK 1 mutation is an important risk factor for the development of pancreatic cancer. To investigate the genetic difference between sporadic PCa and CPPCa, we investigated several factors involved in the pathogenesis of PCa in 6 CPPCa and 15 sporadic PCa patients. The factors examined were genes including K-ras, p53, smad 4, p-smad 1, CXCL 14, NF-kB subunit p65 and Wnt 5a. No significant difference was found in the comparative examination of these factors, suggesting that the molecular disorders appeared to occur similarly in CPPCa as well as sporadic PCa. To assess the role of fibrosis in pancreatic carcinogenesis, we investigated the effects of pancreatic stellate cells (PSCs), which are largely responsible for pancreatic fibrogenesis, on duct cells, in vitro and in vivo. Activated PSCs were found surrounding precancerous duct cells in the tissues of a dimethylbenzanthracene mouse model and those of human PCa. Consistently, human pancreatic epithelial duct cells cultured with PSC conditioned media showed increased cell proliferation and colony formation, suggesting that PSCs may promote pancreatic ductal tumorigenesis.

The role of fibroblast growth factors in tumor growth

Biological processes that drive cell growth are exciting targets for cancer therapy. The fibroblast growth factor (FGF) signaling network plays a ubiquitous role in normal cell growth, survival, differentiation, and angiogenesis, but has also been implicated in tumor development. Elucidation of the roles and relationships within the diverse FGF family and of their links to tumor growth and progression will be critical in designing new drug therapies to target FGF receptor (FGFR) pathways. Recent studies have shown that FGF can act synergistically with vascular endothelial growth factor (VEGF) to amplify tumor angiogenesis, highlighting that targeting of both the FGF and VEGF pathways may be more efficient in suppressing tumor growth and angiogenesis than targeting either factor alone. In addition, through inducing tumor cell survival, FGF has the potential to overcome chemotherapy resistance highlighting that chemotherapy may be more effective when used in combination with FGF inhibitor therapy. Furthermore, FGFRs have variable activity in promoting angiogenesis, with the FGFR-1 subgroup being associated with tumor progression and the FGFR-2 subgroup being associated with either early tumor development or decreased tumor progression. This review highlights the growing knowledge of FGFs in tumor cell growth and survival, including an overview of FGF intracellular signaling pathways, the role of FGFs in angiogenesis, patterns of FGF and FGFR expression in various tumor types, and the role of FGFs in tumor progression.

Mechanisms of KGF mediated signaling in pancreatic duct cell proliferation and differentiation

BACKGROUND

Keratinocyte growth factor (KGF; palifermin) is a growth factor with a high degree of specificity for epithelial cells. KGF is an important effector of epithelial growth and tissue homeostasis in various organs including the pancreas. Here we investigated the intracellular signaling pathways involved in the mediation of pancreatic ductal cell proliferation and differentiation induced by exogenous KGF during beta-cell regeneration in diabetic rat.

METHODOLOGY AND RESULTS

In vitro and in vivo duct cell proliferation was measured by BrdU incorporation assay. The implication of MAPK-ERK1/2 in the mediation of KGF-induced cell proliferation was determined by inactivation of this pathway, using the pharmacological inhibitor or antisense morpholino-oligonucleotides against MEK1. In vivo KGF-induced duct cell differentiation was assessed by the immunolocalization of PDX1 and Glut2 in ductal cells and the implication of PI3K/AKT in this process was investigated. We showed that KGF exerted a potent mitogenic effect on ductal cells. Both in vitro and in vivo, its effect on cell proliferation was mediated through the activation of ERK1/2 as evidenced by the abolition of duct cell proliferation in the context of MEK/ERK inactivation. In vivo, KGF treatment triggered ductal cell differentiation as revealed by the expression of PDX1 and Glut2 in a subpopulation of ductal cells via a PI3K-dependent mechanism.

CONCLUSION

Here we show that KGF promotes beta-cell regeneration by stimulating duct cell proliferation in vivo. Moreover, we demonstrated for the first time that KGF directly induces the expression of PDX1 in some ductal cells thus inducing beta-cell neogenesis. We further explored the molecular mechanisms involved in these processes and showed that the effects of KGF on duct cell proliferation are mediated by the MEK-ERK1/2 pathway, while the KGF-induced cell differentiation is mediated by the PI3K/AKT pathway. These findings might have important implications for the in vivo induction of duct-to-beta cell neogenesis in patients with beta-cell deficiency.

Nestin expression correlates with nerve and retroperitoneal tissue invasion in pancreatic cancer

Nestin was first described as an intermediate filament protein expressed in neuroepithelial stem cells. Nestin expression has also been reported in brain tumors, schwannomas, gastrointestinal stromal tumors, and melanomas. In the pancreas, Nestin expression has been detected in exocrine and mesenchymal cells, including stellate cells, pericytes, and endothelial cells. In the present study, we examined Nestin expression in human pancreatic ductal adenocarcinoma and sought to determine its role in this malignancy. Reverse transcription-polymerase chain reaction analysis demonstrated the presence of Nestin mRNA in all 10 tested pancreatic cancer cell lines, and quantitative reverse transcription-polymerase chain reaction revealed that Nestin mRNA levels were highest in PANC-1 cells and lowest in PK-8 cells. Immunofluorescent analysis revealed that Nestin localized in the outer cytoplasm of PANC-1 cells. Nestin immunoreactivity was present in the cancer cells in 20 (33.3%) of 60 cancer cases, and its expression was confirmed by in situ hybridization. Nestin expression was also increased in peripheral nerve fibers adjacent to cancer cells and in peripheral nerve fibers invaded by cancer cells. Clinicopathologically, there was a statistically significant association between Nestin expression in pancreatic cancer cells and nerve invasion (P = .010) and the presence of cancer cells in the tumor resection margins (P = .003). Nestin-positive cases exhibited similar survival after resection by comparison with Nestin-negative cases, irrespective of whether they were given adjuvant therapy. These findings indicate that Nestin expression in pancreatic cancer cells may contribute to nerve and stromal invasion in this malignancy.

FGF10/FGFR2 signal induces cell migration and invasion in pancreatic cancer

Pancreatic cancer has one of the highest mortalities among all malignancies and there is an urgent need for new therapy. This might be achieved by resolving the detailed biological mechanism, and in this study we examined how pancreatic cancer cells develop aggressive properties by focusing on signalling through the fibroblast growth factor (FGF)10 and FGF receptor (FGFR)2, which play important roles in pancreatic organogenesis. Immunostaining of pancreatic cancer tissues showed that FGFR2 was expressed in cancer cells, whereas FGF10 was expressed in stromal cells surrounding the cancer cells. Patients with high FGFR2 expression in cancer cells had a shorter survival time compared to those with low FGFR2 expression. Fibroblast growth factor 10 induced cell migration and invasion of CFPAC-1 and AsPC-1 pancreatic cancer cells through interaction with FGFR2-IIIb, a specific isoform of FGFR2. Fibroblast growth factor 10 also induced expression of mRNA for membrane type 1-matrix metalloproteinase (MT1-MMP) and transforming growth factor (TGF)-β1, and increased secretion of TGF-β1 protein from these cell lines. These data indicate that stromal FGF10 induces migration and invasion in pancreatic cancer cells through interaction with FGFR2, resulting in a poor prognosis. This suggests that FGF10/FGFR2 signalling is a promising target for new molecular therapy against pancreatic cancer.

Selective expansion of the beta-cell compartment in the pancreas of keratinocyte growth factor transgenic mice

Epithelial-mesenchymal interactions are essential for growth, differentiation, and regeneration of exocrine and endocrine cells in the pancreas. The keratinocyte growth factor (KGF) is derived from mesenchyme and has been shown to promote epithelial cell differentiation and proliferation in a paracrine fashion. Here, we have examined the effect of ectopic expression of KGF on pancreatic differentiation and proliferation in transgenic mice by using the proximal elastase promoter. KGF transgenic mice were generated following standard procedures and analyzed by histology, morphometry, immunohistochemistry, Western blot analysis, and glucose tolerance testing. In KGF transgenic mice, the number of islets, the average size of islets, and the relation of endocrine to exocrine tissue are increased compared with littermate controls. An expansion of the beta-cell population is responsible for the increase in the endocrine compartment. Ectopic expression of KGF results in proliferation of beta-cells and pancreatic duct cells most likely through activation of the protein kinase B (PKB)/Akt signaling pathway. Glucose tolerance and insulin secretion are impaired in transgenic animals. These results provide evidence that ectopic expression of KGF in acinar cells promotes the expansion of the beta-cell lineage in vivo through activation of the PKB/Akt pathway. Furthermore, the observed phenotype demonstrates that an increase in the beta-cell compartment does not necessarily result in an improved glucose tolerance in vivo.

Selective over-expression of fibroblast growth factor receptors 1 and 4 in clinical prostate cancer

Fibroblast growth factor receptors (FGFRs) mediate the tumourigenic effects of FGFs in prostate cancer. These receptors are therefore potential therapeutic targets in the development of inhibitors to this pathway. To identify the most relevant targets, we simultaneously investigated FGFR1-4 expression using a prostate cancer tissue microarray (TMA) and in laser capture microdissected (LCM) prostate epithelial cells. In malignant prostates (n = 138) we observed significant FGFR1 and FGFR4 protein over-expression in comparison with benign prostates (n = 58; p < 0.0001). FGFR1 was expressed at high levels in the majority of tumours (69% of grade 3 or less, 74% of grade 4 and 70% of grade 5), while FGFR4 was strongly expressed in 83% of grade 5 cancers but in only 25% of grade 1-3 cancers (p < 0.0001). At the transcript level we observed a similar pattern, with FGFR1 and FGFR4 mRNA over-expressed in malignant epithelial cells compared to benign cells (p < 0.0005 and p < 0.05, respectively). While total FGFR2 was increased in some cancers, there was no association between expression and tumour grade or stage. Transcript analysis, however, revealed a switch in the predominant isoform expressed from FGFR2IIIb to FGFR2IIIc among malignant epithelial cells. In contrast, protein and transcript expression of FGFR3 was very similar between benign and cancer biopsies. The functional effect of targeting FGFR4 in prostate cancer cells has not previously been investigated. In in vitro experiments, suppression of FGFR4 by RNA interference effectively blocked prostate cancer cell proliferation (p < 0.0001) and invasion (p < 0.001) in response to exogenous stimulation. This effect was evident regardless of whether the cells expressed the FGFR4 Arg388 or Gly388 allele. In parallel experiments, FGFR3 suppression had no discernible effect on cancer cell behaviour. These results suggest evidence of selective over-expression of FGFR1 and FGFR4 in clinical prostate cancer and support the notion of targeted inhibition of these receptors to disrupt FGF signalling.

Keratinocyte growth factor-transfection-stimulated adhesion of colorectal cancer cells to extracellular matrices

The keratinocyte growth factor (KGF) regulates cell growth and behavior in an autocrine or paracrine manner. In colorectal cancer tissues, KGF is expressed in tumor cells and adjacent stromal fibroblasts. We have constructed a KGF-gene-transfected cell line (HCT15-KGF) from a colorectal cancer cell line, HCT-15, that expresses the KGF receptor, and studied the effects of KGF on cell behavior, particularly growth and adhesion to extracellular matrices (ECMs). The amount of KGF secreted from HCT15-KGF was significantly higher than that from a mock-transfected cell line (HCT15-MOCK). The modes of growth of these cell lines were similar. The degree of adhesion of HCT15-KGF to ECMs, including type-IV collagen and fibronectin was higher than that of HCT15-MOCK. The expressions of integrins in both cell lines were not significantly different. However, extracellular-regulated kinase-1 and -2 (ERK1/2) phosphorylation and focal adhesion kinase (FAK) expression that regulate the adhesive functions of integrin families were enhanced in HCT15-KGF. U0126, an inhibitor of the ERK upstream regulator MEK, attenuated the adhesion and spreading of HCT15-KGF cells to type-IV collagen. These results indicate that KGF enhances the adhesion of colorectal cancer cells to type-IV collagen through ERK and FAK signaling pathways.

Enhanced expression of keratinocyte growth factor and its receptor correlates with venous invasion in pancreatic cancer

Keratinocyte growth factor (KGF) and KGF receptor (KGFR) have been implicated in cancer growth as well as tissue development and repair. In this study, we examined whether KGF and KGFR have a role in human pancreatic ductal adenocarcinoma (PDAC). KGFR mRNA was expressed in eight pancreatic cancer cell lines, whereas the KGF mRNA was detected in seven of the cell lines and was absent in MIA PaCa-2 cells. KGFR and KGF immunoreactivity were localized in the cancer cells in 41.5 and 34.0% of patients, respectively. There was a significant correlation between KGFR or KGF immunoreactivity and venous invasion and a significant correlation between the presence of both markers and venous invasion, vascular endothelial growth factor (VEGF)-A expression, and poor prognosis. Exogenous KGF increased VEGF-A expression and release in MIA PaCa-2 cells, and PANC-1 cells stably transfected to overexpress KGF-exhibited increased VEGF-A expression. Moreover, short hairpin-KGFR transfection in MIA PaCa-2 cells reduced the stimulatory effect of exogenous KGF on VEGF-A expression. Short hairpin-KGF transfection in KLM-1 cells reduced VEGF-A expression in the cells. KGFR and KGF may act to promote venous invasion and tumor angiogenesis in PDAC, raising the possibility that they may serve as novel therapeutic targets in anti-angiogenic strategies in PDAC.

Keratinocyte growth factor/fibroblast growth factor-7-regulated cell migration and invasion through activation of NF-kappaB transcription factors

Keratinocyte growth factor (KGF)/fibroblast growth factor-7 (FGF-7) is a paracrine- and epithelium-specific growth factor produced by cells of mesenchymal origin. It acts exclusively through FGF-7 receptor (FGFR2/IIIb), which is expressed predominantly by epithelial cells, but not by fibroblasts, suggesting that it might function as a paracrine mediator of mesenchymal-epithelial interactions. KGF/FGF-7 plays an essential role in the growth of epithelial cells and is frequently overexpressed in cancers of epithelial origin such as pancreatic cancer, switching paracrine stimulation of KGF/FGF-7 to an autocrine loop. Less is known, however, about the signaling pathways by which KGF/FGF-7 regulates the response of epithelial cells. To delineate the signaling pathways activated by KGF/FGF-7 and examine cellular response to KGF/FGF-7 stimulation, we performed functional analysis of KGF/FGF-7 action. In this report, we show that KGF/FGF-7 activated nuclear factor kappaB (NF-kappaB), which in turn induced expression of VEGF, MMP-9, and urokinase-type plasminogen activator and increased migration and invasion of KGF/FGF-7-stimulated human pancreatic ductal epithelial cells. Expression of phosphorylation-defective IkappaBalpha (IkappaBalphaS32A,S36A), which blocked NF-kappaB activation, inhibited KGF/FGF-7-induced gene expression and cell migration and invasion. Our results demonstrate for the first time that KGF/FGF-7 induces NF-kappaB activation and that NF-kappaB plays an essential role in regulation of KGF/FGF-7-inducible gene expression and KGF/FGF-7-initiated cellular responses. Thus, these findings identify one signaling pathway for KGF/FGF-7-regulated cell migration and invasion and suggest that paracrine sources of KGF/FGF-7 are one of the malignancy-contributing factors from tumor stroma.

Elevated expression of FGF7 protein is common in human gastric diseases

Growth alterations within the gastric mucosa during chronic gastric inflammation are key steps in gastric cancer development. FGF7, a specific mitogen for epithelial cells, is implicated in epithelial tissue repair and cancer. We investigated FGF7 expression in normal human stomach, and in 35 cases from various gastric pathologies including 23 gastritis and 8 adenocarcinoma cases. Modest FGF7 protein levels were detected in the normal mucosal gland epithelium and in stromal fibroblasts. FGF7 protein levels, however, were markedly increased in the mucosal epithelium of all gastric inflammation cases. A similar elevated expression was also observed in gastric adenocarcinoma. Upregulation of FGF7 protein was associated with a modest increase in FGF7 mRNA expression. Interestingly, high levels of FGF7 anti-sense (AS) RNA were observed in the gastric pathologies, at the same sites where FGF7 protein was upregulated. Altogether, these findings suggest a role for FGF7 in maintaining gastric mucosa integrity, and that FGF7 protein levels are regulated mainly by posttranscriptional mechanisms. The elevated FGF7 protein levels in gastric inflammation and gastric cancer, together with the known oncogenic potential of FGF7, implicate excessive FGF7 signaling in gastric tumorigenesis, and point to FGF7 as an attractive target for gastric cancer prevention and treatment.

Vhnf1 acts downstream of Bmp, Fgf, and RA signals to regulate endocrine beta cell development in zebrafish

Bmp, Fgf, and retinoic acid (RA) signals have been implicated as regulators of pancreas development. However, the integration of these signaling pathways in vivo is not fully understood. Variant hnf1 (Vhnf1) is a transcription factor involved in pancreas, liver, and kidney development and its mutation in zebrafish causes underdeveloped pancreas and liver. We investigated the signaling pathways that regulate vhnf1 expression during pancreas development. First, we showed that Bmp activity is required for vhnf1 expression in the endoderm. In chordin (a Bmp antagonist) morpholino (MO)-injected embryos, vhnf1 expression in endoderm and in endocrine beta cells is expanded. On the other hand, in alk8 (a type I TGFbeta receptor) MO-injected embryos, vhnf1 expression in the endoderm is significantly reduced. Second, we showed that Fgf signaling participates in regulation of pancreas development through the vhnf1 pathway. Third, we demonstrated that RA fails to rescue reduction of insulin expression in vhnf1 mutants, whereas overexpression of vhnf1 restores insulin expression that is repressed by treatment with a RA receptor inhibitor. And finally, we revealed that both Bmp and Fgf signals act genetically upstream of RA in directing pancreas development. Taken together, our data establish that vhnf1 acts downstream of the signaling pathways of RA, Bmp, and Fgf to regulate pancreas development in zebrafish.

Keratinocyte growth factor expression and activity in cancer: implications for use in patients with solid tumors

Keratinocyte growth factor (KGF) is a locally acting epithelial mitogen that is produced by cells of mesenchymal origin and has an important role in protecting and repairing epithelial tissues. Use of recombinant human KGF (palifermin) in patients with hematologic malignancies reduces the incidence and duration of severe oral mucositis experienced after intensive chemoradiotherapy. These results suggest that KGF may be useful in the treatment of patients with other kinds of tumors, including those of epithelial origin. However, its application in this context raises issues that were not pertinent to its use in hematologic cancer because epithelial tumor cells, unlike blood cells, often express the KGF receptor (FGFR2b). Thus, it is important to examine whether KGF could promote the growth of epithelial tumors or protect such tumor cells from the effects of chemotherapy agents. Analyses of KGF and FGFR2b expression in tumor specimens and of KGF activity on transformed cells in vitro and in vivo do not indicate a definitive role for KGF in tumorigenesis. On the contrary, restoring FGFR2b expression to certain malignant cells can induce cell differentiation or apoptosis. However, other observations suggest that, in specific situations, KGF may contribute to epithelial tumorigenesis. Thus, further studies are warranted to examine the nature and extent of KGF involvement in these settings. In addition, clinical trials in patients with solid tumors are underway to assess the potential benefits of using KGF to protect normal tissue from the adverse effects of chemoradiotherapy and its possible impact on clinical outcome.

N-cadherin and keratinocyte growth factor receptor mediate the functional interplay between Ki-RASG12V and p53V143A in promoting pancreatic cell migration, invasion, and tissue architecture disruption

The genetic basis of pancreatic ductal adenocarcinoma, which constitutes the most common type of pancreatic malignancy, involves the sequential activation of oncogenes and inactivation of tumor suppressor genes. Among the pivotal genetic alterations are Ki-RAS oncogene activation and p53 tumor suppressor gene inactivation. We explain that the combination of these genetic events facilitates pancreatic carcinogenesis as revealed in novel three-dimensional cell (spheroid cyst) culture and in vivo subcutaneous and orthotopic xenotransplantation models. N-cadherin, a member of the classic cadherins important in the regulation of cell-cell adhesion, is induced in the presence of Ki-RAS mutation but subsequently downregulated with the acquisition of p53 mutation as revealed by gene microarrays and corroborated by reverse transcription-PCR and Western blotting. N-cadherin modulates the capacity of pancreatic ductal cells to migrate and invade, in part via complex formation with keratinocyte growth factor receptor and neural cell adhesion molecule and in part via interaction with p120-catenin. However, modulation of these complexes by Ki-RAS and p53 leads to enhanced cell migration and invasion. This preferentially induces the downstream effector AKT over mitogen-activated protein kinase to execute changes in cellular behavior. Thus, we are able to define molecules that in part are directly affected by Ki-RAS and p53 during pancreatic ductal carcinogenesis, and this provides a platform for potential new molecularly based therapeutic interventions.

Defined localization of nestin-expressing cells in L-arginine-induced acute pancreatitis

OBJECTIVE

Nestin is a stem cell marker originally described as an intermediate filament protein expressed in neuroepithelial stem cells. In the pancreas, a small number of nestin-expressing cells, which are believed to represent either stem cells or progenitor cells, are known to be present in islets, as well as in some stellate cells, pericytes, and endothelial cells. We monitored pancreatic nestin expression to delineate the location of stem cells/progenitor cells in the pancreas after L-arginine-induced pancreatitis.

METHODS

Male Wistar rats received 2 intraperitoneal injections of L-arginine, each consisting of 250 mg/100 g of body weight, and were killed 3, 6, and 12 hours and 1, 4, 7, and 14 days later.

RESULTS

Serum amylase and lipase levels increased after L-arginine injection, maximal levels occurring at 3 and 12 hours postinjection, respectively. Six hours after L-arginine injection, interstitial edema was observed in the pancreas, whereas on day 4 postinjection, there was severe pancreatic necrosis. Neovascularization and ductal-ductular proliferation were also present in the pancreas. Immunohistochemical analysis revealed increased Ki-67 labeling in acinar cells and capillary endothelial cells. Immunoblotting using antinestin antibody revealed increased nestin expression after L-arginine injection. In the control rat pancreas, nestin immunoreactivity was detected in a few capillary endothelial cells in some islets. After L-arginine injection, nestin was expressed in proliferating capillary endothelial cells, in stellate cells surrounding ductular structures and in submesothelial cells.

CONCLUSIONS

Transient nestin expression occurs in specific cell types during the proliferative stage after recovery from L-arginine-induced pancreatitis and may represent the contribution of stem cells and/or progenitor cells to the regenerative capacity of the pancreas.

EGF-induced proliferation of adult human pancreatic duct cells is mediated by the MEK/ERK cascade

Human postnatal pancreatic duct cells are a potential source of new beta cells. Factors regulating proliferation of human pancreatic duct cells in vitro are unknown. In several other cell types, this process is influenced by ligands of the ErbB receptor family. The expression and functionality of the ErbB family members and their possible role in duct cell proliferation were determined. In cultured adult human pancreatic duct cells the different members of the ErbB family (ErbB1-4) were present at transcript and protein level. Stimulation of the duct cells with epidermal growth factor (EGF) and betacellulin results in Tyr-phosphorylation of ErbB1 and ErbB2, followed by activation of Shc, MEK1/2 and ERK1/2. Duct cells with activated ErbB signaling changed morphology and motility. EGF induced proliferation of a fraction of the duct cells and treatment with PD98059 prevented Ki67 expression in EGF-supplemented cells. When transduced with recombinant adenovirus expressing constitutively activated MEK1, duct cells proliferate and spread even in the absence of EGF. Importantly, the adult human duct cells retain their capacity to recapitulate ngn3-induced embryonic (neuro)endocrine differentiation after proliferation. Therefore, the present data support a possible role for human adult pancreatic duct cells, following expansion and transdifferentiation, as a source of insulin by transplantation to type I diabetes patients.

Keratinocyte growth factor/fibroblast growth factor 7, a homeostatic factor with therapeutic potential for epithelial protection and repair

Keratinocyte growth factor (KGF) is a paracrine-acting, epithelial mitogen produced by cells of mesenchymal origin. It is a member of the fibroblast growth factor (FGF) family, and acts exclusively through a subset of FGF receptor isoforms (FGFR2b) expressed predominantly by epithelial cells. The upregulation of KGF after epithelial injury suggested it had an important role in tissue repair. This hypothesis was reinforced by evidence that intestinal damage was worse and healing impaired in KGF null mice. Preclinical data from several animal models demonstrated that recombinant human KGF could enhance the regenerative capacity of epithelial tissues and protect them from a variety of toxic exposures. These beneficial effects are attributed to multiple mechanisms that collectively act to strengthen the integrity of the epithelial barrier, and include the stimulation of cell proliferation, migration, differentiation, survival, DNA repair, and induction of enzymes involved in the detoxification of reactive oxygen species. KGF is currently being evaluated in clinical trials to test its ability to ameliorate severe oral mucositis (OM) that results from cancer chemoradiotherapy. In a phase 3 trial involving patients who were treated with myeloablative chemoradiotherapy before autologous peripheral blood progenitor cell transplantation for hematologic malignancies, KGF significantly reduced both the incidence and duration of severe OM. Similar investigations are underway in patients being treated for solid tumors. On the basis of its success in ameliorating chemoradiotherapy-induced OM in humans and tissue damage in a variety of animal models, additional clinical applications of KGF are worthy of investigation.

Angiogenesis and antiangiogenic strategies in pancreatic cancer

Despite numerous advances in the treatment of solid tumors, the prognosis of patients diagnosed with pancreatic cancer remains dismal. Results of both surgical and non-surgical treatment for pancreatic cancer have been extremely disappointing because of the tumors propensity to metastasize, failure of chemotherapy to achieve adequate levels within the tumor, and resistance of pancreatic cancer to cytotoxic agents. Current chemotherapeutic agents and radiation treatments rely on the rapidly dividing nature of tumor cells and are limited by their cytotoxic effects on normal cells. The need to exploit the difference between normal and malignant cells has resulted in an enormous amount of research into the process of tumor neovascularization. New agents are currently being developed that block tumor growth and metastasis through inhibition of angiogenesis. This article reviews the process of angiogenesis and antiangiogenic strategies with a special emphasis on pancreatic cancer.

Adenovirus-mediated transfer of a truncated fibroblast growth factor (FGF) type I receptor blocks FGF-2 signaling in multiple pancreatic cancer cell lines

Pancreatic ductal adenocarcinomas (PDACs) overexpress several members of the fibroblast growth factor (FGF) family of ligands and the type I FGF receptor (FGFR-1), and enhanced FGF-2 protein levels correlate with shorter postoperative survival of patients with PDAC. In this study, we investigated the effects of FGF-2 on cell proliferation and mitogen-activated protein kinase (MAPK) activation before and after abrogation of FGFR-1-dependent signaling in 4 pancreatic cancer cell lines (ASPC-1, COLO-357, MIA-PaCa-2, and PANC-1). Signaling was blocked by infecting the cells with an adenoviral vector encoding for a truncated FGFR-1 (AdtrFGFR-1). FGF-2 enhanced the growth of all 4 cell lines and activated MAPK in 3 of these cell lines. Infection with the AdtrFGFR-1 virus resulted in abundant expression of the truncated FGFR-1 at the RNA and protein level, markedly attenuated FGF-2-induced proliferation in all 4 tested cell lines, and decreased FGF-2-dependent MAPK activation in the 3 cell lines in which FGF-2 activated this pathway. These findings suggest that FGFR-1-mediated mitogenesis in multiple pancreatic cancer cells can be efficiently blocked with an adenoviral vector encoding a truncated FGFR-1, raising the possibility that AdtrFGFR-1 may ultimately have a therapeutic role in PDAC.

Lumican expression is associated with the formation of mesenchyme-like elements in salivary pleomorphic adenomas

Pleomorphic adenomas are the most common salivary gland tumour. Although this tumour is considered to be of epithelial origin, it contains 'mesenchyme'-like elements histologically. Lumican is a keratan sulphate proteoglycan that belongs to the small leucine-rich repeat (LRR) proteoglycans and has been reported to be associated with cartilage formation. These findings suggest that lumican expression may be related to the chondroid component in pleomorphic adenomas. To investigate this hypothesis, the present study investigated the expression and localization of lumican in 20 normal human salivary glands and 35 pleomorphic adenomas. Firstly, immunohistochemistry for lumican was performed with pepsin pretreatment. In normal salivary glands, lumican was deposited in the periductal regions. In pleomorphic adenomas, it was predominantly deposited in the hyaline (100%) and fibrous areas (89.4%). In 16 tumours (66.7%), lumican was also deposited in the chondroid areas. Without pepsin pretreatment, lumican was identified in myoepithelial cells in myxoid areas, lacuna cells in chondroid areas, and in the cytoplasm of inner ductal cells. In situ hybridization revealed lumican mRNA expression mainly in the inner cells, the neoplastic myoepithelial cells, and the lacuna cells. These results suggest that lumican is associated with the formation of 'mesenchyme'-like structures in pleomorphic adenomas. In conclusion, normal salivary glands express lumican, which appears to be related to stromal maintenance, and pleomorphic adenomas express lumican mRNA and protein, which may play important roles in the formation of 'mesenchyme'-like areas in this type of tumour.

Keratinocyte growth factor and beta-cell differentiation in human fetal pancreatic endocrine precursor cells

AIMS AND HYPOTHESIS

Keratinocyte growth factor (KGF) is a member of the heparin-binding fibroblast growth factor family with a high degree of specificity for epithelial cells in vitro and in vivo. Our aim was to study the effect of KGF on beta-cell growth and differentiation on islet-like cell clusters derived from human fetal pancreas.

METHODS

We investigated the effects of KGF, in vitro, on beta-cell differentiation from undifferentiated pancreatic precursor cells and in vivo after transplantating human fetal pancreatic cells into athymic rats treated with KGF.

RESULTS

Treatment of islet-like cell clusters with KGF in vitro did not change the number of insulin producing cells, as measured by the measurement of insulin content or DNA. The in vivo treatment of recipient rats with KGF increased the number of beta cells within the grafts 8 weeks after transplantation. At this time, glucose-stimulated insulin secretion was evaluated by glucose stimulation tests in rats bearing the transplants. Measurements of human C-peptide concentrations after glucose challenge showed that the newly differentiated beta cells in the KGF-treated group were functionally competent as opposed to the control group, where the graft failed to release insulin appropriately.

CONCLUSION/INTERPRETATION

These findings suggest that in vivo, KGF is capable of inducing human fetal beta-cell expansion. The growth promoting effect of KGF on beta cells occurred mainly through the activation of ductal cell proliferation and their subsequent differentiation into beta cells.

Expression of keratinocyte growth factor receptor (KGFR/FGFR2 IIIb) in vascular smooth muscle cells

Keratinocyte growth factor receptor (KGFR), also known as fibroblast growth factor receptor (FGFR)2 IIIb, is located in many types of epithelial cells and is activated by four known ligands (FGF-1, FGF-3, FGF-7 (also known as KGF) and FGF-10) that are predominantly synthesized by mesenchymal cells. In the early stage of atherosclerosis, vascular smooth muscle cells (VSMC) transform from a contractile to a synthetic phenotype, proliferate and migrate into the intima. Previously, FGF-7 mRNA expression was reported in VSMC, but KGFR mRNA was not detected. In the present study, we attempted to determine whether KGFR is localized in VSMC cultured from rat aorta and VSMC in human normal and atherosclerotic coronary arteries. Expression of KGFR mRNA and its protein was detected in cultured rat VSMC by reverse transcription-polymerase chain reaction and western blot analysis, respectively. Immunohistochemically, KGFR was localized in the VSMC of the outer layer of the media in normal human coronary arteries. Furthermore, it was localized in the VSMC of the media and thickened intima of atherosclerotic arteries. Recombinant FGF-7 and/or FGF-10 proteins stimulated the growth of cultured rat VSMC. These findings indicate that KGFR localized in VSMC may contribute to the proliferation of VSMC in normal and atherosclerotic arteries.

Transient and ectopic expression of lumican by acinar cells in L-arginine-induced acute pancreatitis

Lumican is a member of a small leucine-rich proteoglycan family. We previously found that lumican mRNA and its protein were ectopically and highly expressed in acinar cells in chronic pancreatitis (CP)-like lesions close to pancreatic cancer cells. CP-like lesions are characterized by acinar and ductal-ductular cell proliferation with expanding fibrosis. This finding suggests that lumican is ectopically synthesized by acinar cells under chronic inflammatory conditions and plays a role in fibrosis of the pancreas. However, the expression and role of lumican in acute inflammatory changes of the pancreas are not completely elucidated. In the present study, we aim to clarify whether lumican mRNA and its protein are expressed in exocrine or endocrine components in acute pancreatitis (AP). For experimental AP, Wistar rats received an intraperitoneal injection of L-arginine. Western blot analysis showed an intense 50-kDa band corresponding to the lumican protein in normal and L-arginine-treated rat pancreas. After L-arginine injection, three intense bands at 42, 57, and 92 kDa were detected on day 1. Immunohistochemically, the lumican protein was localized in ductal and a few centroacinar cells in the normal pancreas. After L-arginine injection, an immature fibrosis with fragmented and loose collagen fibers was observed in AP on day 4 and lumican immunoreactivity was detected in the collagen fibers. Lumican mRNA was faintly detected in islet cells in the normal pancreas, but it was strongly expressed in acinar and islet cells on day 1. Furthermore, lumican mRNA was expressed in many proliferating fibroblasts on day 4 by in situ hybridization. These findings indicate that lumican is transiently synthesized by acinar cells and fibroblasts in AP. Lumican proteins synthesized by acinar cells, islet cells, and fibroblasts may contribute to immature and transient fibrosis of AP.