2-Deoxy-d-glucose increases GFAT1 phosphorylation resulting in endoplasmic reticulum-related apoptosis via disruption of protein N-glycosylation in pancreatic cancer cells.

The glycolytic inhibitor 2-deoxy-d-glucose (2DG) causes energy starvation, affecting cell viability in a wide range of cancer cell lines. To determine the action of 2DG in pancreatic cancer, we performed proteomic analysis of pancreatic cancer cell line after 2DG treatment. Eighty proteins showed differential expression and among these, proteins involved in phosphohexose metabolism were upregulated. Up-regulation of glutamine: fructose 6-phosphate aminotransferase 1 (GFAT1), which belongs to the hexosamine biosynthesis pathway (HBP) that produces uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) to maintain glycoprotein, was validated by evaluation of mRNA and protein levels. Therefore, we assessed the amounts of total N-glycoproteins. Unexpectedly, we found a reduction of total N-glycoproteins and phosphorylation of GFAT1 by AMP-activated protein kinase (AMPK). These data may shed light on HBP dysfunction. Furthermore, we found endoplasmic reticulum (ER) stress accompanied by increased expression of ER stress markers, such as glucose response protein 78 (GRP78) and C/EBP-homologous protein (CHOP), in 2DG-treated cells. Moreover, the additive activation of AMPK by metformin (Met) synergistically enhanced the reduction of protein N-glycosylation and cell growth inhibition in the presence of 2DG. These results suggest that 2DG reduces N-glycosylation of proteins following the increase of phosphorylation of GFAT1 and results in the inhibition of cell growth mediated by ER stress in pancreatic cancer cells.

Clinicopathological significance of a solid component in papillary thyroid carcinoma.

AIMS: Solid variant of papillary thyroid carcinoma (SVPTC) is characterized by a solid component (SC) involving more than 50% of the tumour with the preservation of the classical cytological features of papillary thyroid carcinoma (PTC). However, the clinical significance of SC in PTC has been rarely examined. Herein, we investigated retrospectively the clinicopathological features of PTC with various degrees (10-85%) of SC (PTCSC). METHODS AND RESULTS: Patients with PTCSC (n = 27) were stratified into SC-major (SC > 50% of the tumour) and SC-minor (SC < 49%) groups. The clinicopathological parameters were compared to the well-differentiated PTC (WPTC) group (n = 47). Both SC-minor (n = 18) and SC-major (n = 9) groups had increased incidence of a large-sized tumour, extracapsular extension and a high recurrence rate, compared to WPTC. Disease-free survival (DFS) of both SC-minor and SC-major was shorter than that of WPTC (P = 0.035 and P = 0.016, respectively). Overall survival was similar among all the groups. Univariate analysis revealed that SC was associated significantly with a recurrence rate (P = 0.018). Using multivariate analysis, SC appeared to be associated with a recurrence rate with borderline significance (P = 0.055). CONCLUSIONS: Our findings indicate that the presence of SC in PTC, regardless of the proportion, is associated with adverse clinical parameters and a shorter DFS.

Higher expression of EpCAM is associated with poor clinical and pathological responses in breast cancer patients undergoing neoadjuvant chemotherapy.

Neoadjuvant chemotherapy (NAC) is a standard regimen in treatment of breast cancer patients, but some are resistant to NAC. We hypothesized that breast cancer cells overexpressing epithelial cell adhesion molecule (EpCAM) could be resistant to NAC, contributing to a poor prognosis. Seventy patients with breast cancer were treated with NAC. Core needle biopsy (CNB) specimens and resected tumors before and after NAC, respectively, were examined for expression of EpCAM. In resected tumors, high EpCAM expression correlated with lymphovascular invasion status and nuclear grade (P = 0.01 and 0.008, respectively), and was associated with poor pathological and clinical responses (P < 0.001). High tumoral EpCAM expression in resected tumor was independently related to a poor pathological response. Patients with high EpCAM expression before and after NAC (high-to-high group) showed worse pathological and clinical responses (P = 0.008 and <0.001, respectively) than the patients with high and low EpCAM expression before and after NAC, respectively (high-to-low group). The overall survival rate of the high-to-high group appeared shorter compared with the high-to low-group (P = 0.049). Our findings imply that higher levels of EpCAM in breast cancer may be associated with poor response to NAC via a potential chemoresistant effect.

Cytological Assessment of Desmoplastic Malignant Pleural Mesothelioma in an Autopsy Case.

INTRODUCTION: Desmoplastic malignant pleural mesothelioma (DMPM) is a sarcoma-type mesothelioma, comprising approximately 5% of malignant pleural mesotheliomas. Although effusion cytology is commonly used as the primary diagnostic approach for mesothelioma, it may not be useful for DMPM because of the presence of desmoplasia and bland cellular atypia. We report a case, and previously undescribed cytological features, of DMPM that was diagnosed during autopsy. CASE PRESENTATION: A man in his 60s with a history of occupational asbestos exposure was referred to our hospital with right chest pain. A chest CT scan showed right pleural effusion. Thirteen months later, the patient died of respiratory failure. During autopsy, scrape-imprint smears were prepared and cytology of pleural effusions was performed. The scrape-imprint smear samples showed spindle cells with mild nuclear atypia and grooves with fibrous stroma. Pleural effusion cytology revealed spindle cells with mild nuclear atypia, as well as grooves with loose epithelial connections. Histological examination of the right pleura showed spindle cells proliferating with dense collagen fibers, as seen in the cytological samples, thus indicating a diagnosis of DMPM, which was confirmed by fluorescence in situ hybridization. CONCLUSION: Cytological procedures such as pleural effusion cytology and scrape-imprinting cytology may help in diagnosing rare tumors such as DMPM.

Enhanced expression of lumican inhibited the attachment and growth of human embryonic kidney 293 cells.

Lumican is a member of a small leucine-rich proteoglycan (SLRP) family and it regulates the assembly and diameter of collagen fibers in the extracellular matrix of various tissues. Lumican expression was reported in various kinds of tumor cells. Lumican inhibits the growth of melanoma cells, but the lumican in pancreatic cancer correlated with an advanced stage and retroperitoneal and duodenal invasion. In this study, we clarified whether the enhanced expression of lumican contributes to cellular attachment, growth, colony formation, migration and invasion. HEK 293 cell, stably transfected with lumican cDNA synthesized and secreted a 50 kDa lumican protein at high levels in culture medium. The cells showed a polygonal appearance with long projections and the degree of adhesion of the cells to fibronectin was lower than that of empty vector transfected control cells (mock cells). In contrast, the degree of adhesion of the cells to type I collagen was not different from that of mock cells. The expression levels of alpha5 integrin, the major integrin subunit for fibronectin, were lower in lumican-transfected HEK cells than in mock cells. Furthermore, lumican-transfected HEK cells showed reduced growth rates in vitro and did not form colonies in soft agar. Phosphorylation of AKT, extracellular signal-regulated kinase (ERK) 1/2 and mammalian target of rapamycin (mTOR) decreased in the lumican-transfected HEK cells. Cell migration and invasion were not altered in lumican-transfected HEK cells and mock cells. These findings indicate that the 50kDa lumican protein plays important roles in the inhibition of HEK cell attachment and growth, and it might inhibit the activation of integrin pathways.

Morphological and cytoskeletal changes of pancreatic cancer cells in three-dimensional spheroidal culture.

Three-dimensional (3D) cell cultures are expected to mimic in vivo environments. We used a NanoCulture plate to determine the spheroid-forming ability of pancreatic ductal adenocarcinoma (PDAC) cell lines and compared the morphology and expression of cytoskeletal proteins of PDAC cells to those in two-dimensional (2D) cultures. All examined PDAC cells grew as monolayers in 2D culture. PANC-1 and KLM-1 formed spheroids in 3D culture, but PK-45H and MIAPaCa-2 did not. Strong expression of F-actin was observed in the cells attached to the surface of the plate, which formed cell projections in 3D culture. F-actin was detected on the grids of the NanoCulture plate in PANC-1 cells but not in PK-45H. The levels of tubulin expression in cells were higher in 3D culture than in 2D culture. The expression level of E-cadherin mRNA in PANC-1 and KLM-1 was higher than that in PK-45H and MIAPaCa-2. In conclusion, PDAC cells showed morphological changes, spheroid formation, and alterations of cytoskeletal proteins in 3D culture. E-cadherin might be one of the key molecules involved in spheroid formation of PDAC cells. The 3D spheroidal culture system was a useful method for cell imaging with contrast-phase microscopy and confocal microscopy.

Keratinocyte growth factor induces vascular endothelial growth factor-A expression in colorectal cancer cells.

Keratinocyte growth factor (KGF), which is also called fibroblast growth factor (FGF)-7, belongs to the FGF family. KGF is not commonly produced by human cancer cells, but the KGF receptor (KGFR) is expressed in most cancer cells and particularly highly expressed in well-differentiated types of cancer. Recently, it has been reported that vascular endothelial growth factor (VEGF)-A expression is induced by KGF in pancreatic cancer cells. VEGF-A is produced by some cancer cells and plays important roles in the angiogenesis and metastasis of cancer cells including those in the colorectum. In this study, we examined whether recombinant human KGF (rhKGF) induces major angiogenic growth factors including VEGF-A, FGF-2 and hepatocyte growth factor (HGF) in human colorectal cancer cells (HCT-15), which express a high level of KGFR, but a low or negligible level of KGF. rhKGF significantly increased the VEGF-A expression level in a serum-free medium of HCT-15 cells, but FGF-2 and HGF expression levels were too low to detect. Furthermore, the expression levels of the angiogenic growth factors were evaluated in KGF-transfected HCT-15 cells, which were induced to stably overexpress KGF by KGF gene transfection and mock-transfected cells (Mock). KGF and VEGF-A expression levels in the cells and the protein concentrations in serum-free medium were significantly higher in KGF-transfected HCT-15 cells than in Mock cells. In contrast, the FGF-2 and HGF mRNA expression levels were not significantly different between KGF-transfected HCT-15 cells and Mock cells and the protein concentrations in serum-free medium of the cells were below the detection level. These findings suggest that administration of rhKGF and over-expression of endogenous KGF genes in colorectal cancer cells increase VEGF-A production and may relate to angiogenesis in cancer.

Toll­like receptor 4 plays a tumor­suppressive role in cutaneous squamous cell carcinoma.

Toll­like receptor 4 (TLR4), a key regulator of the innate immune system, is expressed not only in immune cells, but also in a number of cancer cells. A biological role for TLR4 in cutaneous squamous cell carcinoma (SCC), however, is unclear. In this study, we first examined TLR4 expression and localization in cases of SCC, actinic keratosis (AK) and Bowen's disease (BD) by immunohistochemistry. TLR4 expression was significantly higher in the SCC than in the AK or BD tissues. We then determined the TLR4 expression level in vivo, in 3 histological subtypes of SCC. TLR4 expression in poorly differentiated SCC was significantly lower compared with that of the moderately and well­differentiated type. In addition, the CD44 immunoreactivity tended to be high in the cell membrane of poorly differentiated SCC. Of note, poorly differentiated SCC is a risk factor of unfavorable outcomes in affected patients. We then assessed the biological role of TLR4 in HSC­1 and HSC­5 SCC cells and HaCaT human keratinocytes. TLR4 knockdown by transfection with siRNA accelerated HSC­1 and HaCaT cell migration and invasion compared to the control siRNA­transfected cells. TLR4 knockdown resulted in an increased CD44 expression and in an enhanced filopodia protrusion formation, particularly in HSC­1. On the whole, these results suggest that a reduced TLR4 expression enhances the malignant features in SCC cases and cultured SCC cell lines. TLR4 may thus play an anti­tumor role in cutaneous SCC.

Expression and roles of lumican in lung adenocarcinoma and squamous cell carcinoma.

Lumican is a member of a small leucine-rich proteoglycan family and is highly expressed in several types of cancer cells and/or stromal tissue. Lumican expression in the cytoplasm in advanced colorectal cancer correlates with poor patient prognosis. The expression of lumican in stromal tissues is associated with a high tumor grade, a low estrogen receptor expression level, and young age in breast cancer and is associated with tumor invasion and advanced stage in pancreatic cancer. In this study, we examined the expression and role of lumican in lung cancer including adenocarcinoma (ADC) and squamous cell carcinoma (SqCC). Immunohistochemically, lumican was weakly expressed in vascular smooth muscle cells, perivascular and peribronchial connective tissues and bronchial epithelium of normal lung tissues. In lung cancer tissues, lumican was localized in the cytoplasm of cancer cells and/or stromal tissues adjacent to cancer cells. In ADC, the expression level of lumican in cancer cells correlated with pleural invasion and larger tumor size, but that of lumican in stromal tissues did not correlate with clinicopathological factors. In SqCC, the expression level of lumican in cancer cells correlated with formation of a keratinized pattern, and stromal lumican expression correlated with vascular invasion. In SqCC and ADC, the expression level of lumican in cancer cells did not correlate with patient prognosis. In lung cancer cell lines, lumican mRNA and protein were expressed in LC-1/Sq and EBC-1 cells established from SqCC, and A549, RERF-LC-KJ and PC-3 cells from ADC. The molecular weight of lumican extracted from the cytoplasm of lung cancer cells differed from that in the culture medium owing to glycosylation of the protein. These findings suggest that the expression pattern and the glycosylated type of lumican in cells and stromal tissues correlate with the aggressiveness of lung SqCC and ADC.

Role of lumican in cancer cells and adjacent stromal tissues in human pancreatic cancer.

Lumican is a member of a small leucine-rich proteoglycan family and its overexpression has been reported in carcinoid tumor, breast, colorectal, neuroendocrine cell, uterine cervical and pancreatic cancers. The expression of lumican in stromal tissues in breast cancer is associated with a high tumor grade, a low estrogen receptor expression level and young age. Lumican expression in the cytoplasm in advanced colorectal cancer is correlated with a poor prognosis. Lumican expression was previously reported in pancreatic cancer, but the role of lumican in pancreatic cancer is still not well understood. In this study, we aimed to clarify the role of lumican in pancreatic cancer. Reverse-transcription polymerase chain reaction and Western blot analyses revealed lumican mRNA and protein expression in six pancreatic ductal adenocarcinoma cell lines (i.e. PANC-1, MIA PaCa-2, KLM-1, Capan-1, PK-1 and PK-8). On the basis of its immunoreactivity, lumican was found to be localized in islet cells of normal pancreatic tissues, but not in exocrine cells. In pancreatic cancer tissues, lumican was predominantly localized in the cytoplasm of cancer cells in 30 out of 53 (56.6%) cancer patients, whereas lumican was detected in stromal tissues in 36 out of 53 (67.9%) cancer patients. Lumican expression in pancreatic cancer cells did not correlate with clinicopathological factors, whereas lumican expression in stromal tissues correlated with the female gender, advanced stage, retroperitoneal and duodenal invasion and residual tumor (p=0.030, 0.038, 0.049, 0.049 and 0.048, respectively). Patients with lumican-positive cancer cells tended to survive longer than those with lumican-negative cancer cells (p=0.286), but patients with lumican-positive stromal tissues had shorter survival than those with lumican-negative stromal tissues (p=0.062). These results suggest that lumican in stromal tissues plays an important role in the growth and invasion of pancreatic cancer.

Expression of MRP1 and ABCG2 is associated with adverse clinical outcomes of papillary thyroid carcinoma with a solid component.

Solid variant of papillary thyroid carcinoma (PTC) is characterized by a solid component (SC) retaining classical cytological features of PTC. Despite some controversies, PTC with SC (PTCSC) cases have poor prognosis compared with well-differentiated PTC. We investigated if cancer stem cells (CSCs) may have a role in pathogenesis of PTCSC. PTCSC tumors (n=27) were histologically represented by a mixture of papillary component (PC) and varying degrees of SC involving 10% to 85% of the tumor. Immunohistochemical expression of CSC markers ABCG2 and MRP1, and HBME1 and CK19 was compared between SC and PC within each tumor in association with clinicopathological parameters. ABCG2 and MRP1 were highly expressed in SC, whereas their expression was limited or absent in PC (P=.04 and .002, respectively). In contrast, expression of HBME1 and CK19 appeared higher in PC than in SC (P=.08 and .02, respectively). Higher expression of ABCG2 was associated with higher incidence of large-sized SC (P=.01). Higher expression of MRP1 was associated with higher incidence of lymphovascular invasion (P=.049). Higher expression of ABCG2 and MRP1, and lower expression of CK19 in SC were associated with higher tumor recurrence rate (P=.02, .01, and .02, respectively), and shorter disease-free survival (P<.001 for all the variables). Our findings indicate that the tumor cells harboring CSC-like characteristics in SC could contribute to the pathogenesis of PTCSC and might account for the poor disease prognosis.

Insulin-like growth factor 2 mRNA-binding protein-3 as a marker for distinguishing between cutaneous squamous cell carcinoma and keratoacanthoma.

In the histopathological diagnosis of cutaneous tumors, the differential diagnosis of squamous cell carcinoma (SCC) with crateriform architecture and keratoacanthoma (KA) is often difficult so an accurate understanding of the biological features and the identification of reliable markers of SCC and KA are crucial issues. Insulin-like growth factor 2 mRNA-binding protein-3 (IGF2BP3, also known as IMP3) is thought of as a bona fide oncofetal protein, which is overexpressed and is involved in cell proliferation, migration, and invasion in several kinds of tumors. However, the role of IMP3 in cutaneous SCC and KA has not been well studied. Therefore, we focused on studying the biological functions of IMP3 in SCC and KA. In human skin SCC cell lines, HSC-1 and HSC-5, and the human keratinocyte cell line, HaCaT, IMP3 mRNA levels were significantly higher than that of normal human skin. The knockdown of IMP3 expression reduced the proliferation of HSC-1, and significantly reduced invasion by HSC-1 and HSC-5. In contrast, the knockdown of IMP3 did not significantly affect invasion by HaCaT cells. In immunohistochemical studies of SCC and KA tissues, the Ki-67 labeling index (LI) of the suprabasal cell layer was significantly higher in SCC, compared with KA tissues and the tumor-free margin (TFM) adjacent to SCC and KA. Most SCC tissues stained strongly positive for IMP3, but KA tissues and TFM were mostly negative for IMP3. The Ki-67 LI of the IMP3-positive group was significantly higher than that of the IMP3-negative group in the suprabasal cell layer of SCC. These results suggest that IMP3 plays an important role in proliferation and, more significantly, in the invasion of SCC, and may be a suitable marker for the histopathological diagnosis of SCC with a crateriform architecture and KA. Furthermore, IMP3 may potentially be a new therapeutic target for SCC.

Expression and accumulation of lumican protein in uterine cervical cancer cells at the periphery of cancer nests.

Lumican is a member of a small leucine-rich proteoglycan (SLRP) family and is reported to be overexpressed during the wound healing process of the cornea, and ischemic and reperfused heart. In the carcinomatous tissues, lumican is overexpressed in human breast and pancreatic cancer tissues. In the present study, we aimed to clarify the expression of lumican mRNA and its protein in human cervical cancer cell lines (CaSki, ME-180 and HeLa cells) and their localization in normal and cancerous human cervical tissues. Reverse transcription-polymerase chain reaction and Western blot analysis revealed the expression of lumican mRNA and its protein in CaSki, ME-180 and HeLa cells. No or weak immunoreactivity of the lumican protein was observed in stroma but not in squamous and ductal cells of non-cancerous uterine cervical tissues. In 21 of 28 (75%) cervical cancer cases, the lumican protein was strongly expressed in cancer cells, and accumulated particularly in cancer cells at the periphery of the cancer nests. It was also expressed in the fibroblasts adjacent to the cancer cells. In situ hybridization analysis revealed that lumican mRNA was not expressed in squamous or ductal epithelial cells in non-cancerous tissues, but was expressed in most cancer cells and stromal fibroblasts in uterine cervical cancer tissues. The lumican protein was not localized in normal squamous or ductal cells close to cancer cells, but its mRNA was strongly expressed in the same cells. To our knowledge, this is the first report on lumican synthesized by squamous cell carcinomas. These findings may indicate that the accumulated lumican protein in cancer cells at the periphery of cancer nests may play roles in the growth or invasion of human cervical cancer 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.

External whole-body image of EGFP gene expression.

Whole-body optical imaging is an external and noninvasive procedure that enables the continuous visual monitoring of malignant growth and spread within intact animals. The human colon adenocarcinoma cell-line HCT-15 was transfected with a pIRES 2-EGFP vector, and stable enhanced green fluorescence protein (EGFP) expression was established (Fig.1). Approximately 10(6) HCT-15 EGFP stable transfectant cells were subcutaneously injected into the left flank of six-week-old male Balb/c-nu/nu mice. On post-injection day 78, the size of the subcutaneous tumor was 13.1 mm x 15.4 mm in diameter, as observed using an ORCA-C 7780-20 three-chip cooled color charge-coupled-device camera (Hamamatsu Photonics Systems, Hamamatsu City, Japan). An external fluorescent image of the tumor was acquired through the skin (Fig.2B). The tumor could be seen more clearly once the skin was removed (Fig.2D). Furthermore, in the peritoneal metastasis (Fig.3B) and liver metastasis models (Fig.3D), metastasis could also be seen through the skin. This new technology is a useful method for investigating tumor growth in vivo. In the future, this method could be applied to the detection of peritoneal, liver and lung metastasis in living animals.

Nodular fasciitis in the parotid gland: a case report and review of the literature.

Nodular fasciitis (NF) is a benign, reactive lesion with a self-limiting process. Because NF is rare in the parotid gland and has many cytological similarities to other benign or malignant tumors, cytological misinterpretation is common. The patient, a 30-year-old woman, had a painless mass in her right parotid gland. Fine needle aspiration cytology (FNAC) was performed. Spindle cells with basophilic and well-demarcated cytoplasm were observed in a mucoid-like background. The mucoid-like substance was metachromatic and appeared to be the matrix of PA. Histopathologically, spindle-shaped cells with intervening birefringent mature collagen were arranged in short irregular bundles. Prominent mucoid-like matrixes as well as few infiltrating neutrophils and lymphocytes were found in the background. Lesional cells were positive for CD10 and ß-catenin in the cytoplasm, but negative for cytokeratin, the S-100 protein, CD34, and neurofilament. Ultimately, this patient was diagnosed with NF. In FNAC of the parotid gland region, distinguishing NF from other real tumors is important for deciding treatment strategies.

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.

Secreted 70kDa lumican stimulates growth and inhibits invasion of human pancreatic cancer.

Lumican expression in the stromal tissues of pancreatic ductal adenocarcinoma (PDAC) correlates with tumor invasion, and tends to correlate with poor prognosis. We used gene transfection techniques to examine the biological roles of lumican secreted from PDAC cells. Lumican-transfected PANC-1 cells secreted a 70-kDa lumican protein and had an active ERK pathway. Transfection stimulated PANC-1 cell growth, increased cell adhesion to laminin, inhibited cell invasion, and decreased active matrix metalloproteinase-9. Down-regulation of lumican using siRNA resulted in opposite cell behavior. Thus, the 70-kDa lumican secreted by PDAC cells plays important roles in cell growth and invasion.

Neuroepithelial stem cell marker nestin regulates the migration, invasion and growth of human gliomas.

Nestin, a class VI intermediate filament protein, was originally described as a neuronal stem cell marker during central nervous system development. Nestin is expressed in gliomas, and its expression levels are higher in gliomas with high WHO histopathological classification grades than in those with low grades. In the present study, we examined whether nestin regulates the biological activities of human glioma cells. Immunohistochemically, the nestin expression patterns in 10 human glioblastoma patients were examined. The expression levels of nestin in A172, a human high-grade glioma cell line, and KG-1-C, a human low-grade glioma cell line, were examined using real-time PCR, Western blot and immunofluorescence analyses. An expression vector carrying a short hairpin RNA targeting nestin was stably transfected into A172 (Sh) cells. The effects of decreased expression levels of nestin in Sh cells on cell growth, migration, invasion, adhesion to extracellular matrices and fibrillar actin expression on three-dimensional culture plates were examined. The nestin expression vector was transiently transfected into KG-1-C (Nes) cells, and the effects of the nestin overexpression on cell growth and migration were examined. Nestin was expressed in the cytoplasm of the glioblastoma cells in all cases examined. Sh cells showed marked decreases in the expression levels of nestin mRNA and protein, and the growth rate of Sh cells was lower than that of sham (Sc) cells. In contrast, the adhesion activity of Sh cells to types I and IV collagens, fibronectin and laminin was higher than that of Sc cells. Fibrillar actin was clearly detected at the periphery of colonies of Sh cells at the attachment sites on three-dimensional culture plates. The migration and invasion of Sh cells were markedly inhibited compared with those of Sc cells. In contrast, the levels of nestin expression markedly increased in the Nes cells, which were transiently transfected with the nestin expression vector. The growth rate and motility of Nes cells were higher than those of the mock cells. In conclusion, nestin plays important roles in cell growth, migration, invasion and adhesion to extra-cellular matrices in glioma cells. Nestin may serve as a novel candidate for molecular-targeted therapy for gliomas, including glioblastomas.

Nestin is a novel target for suppressing pancreatic cancer cell migration, invasion and metastasis.

Nestin, is a class VI intermediate filament (IF) that is expressed in 30% of pancreatic ductal adenocarcinoma (PDAC) cases, and its expression in PDAC positively correlates with peripancreatic invasion. An expression vector carrying a short hairpin RNA (shRNA) targeting nestin was stably transfected into PANC-1 and PK-45H human pancreatic cancer cells, which express high nestin levels. Alterations in morphology and alignment of actin filaments and α-tubulin were examined by phase-contrast and immunocytochemistry. Effects on cell growth, migration in scratch and Boyden chamber assays, invasion, cell adhesion, and in vivo growth were determined. Differences in mRNA levels were examined by arrays. Nestin shRNA-transfected cells exhibited decreased nestin expression, a sheet-like appearance with tight cell-cell adhesion, increased expression of filamentous F-actin and E-cadherin, and attenuated migration and invasion, both of which were enhanced following nestin re-expression. Expression of α-tubulin, and in vitro cell growth and adhesion were not altered by nestin down-regulation, whereas hepatic metastases were decreased. Thus, nestin plays important roles in pancreatic cancer cell migration, invasion and metastasis by selectively modulating the expression of actin and cell adhesion molecules, and may therefore be a novel therapeutic target in PDAC.