CXCL8/IL-8 and CXCL12/SDF-1alpha co-operatively promote invasiveness and angiogenesis in pancreatic cancer

CXC-chemokines are involved in the chemotaxis of neutrophils, lymphocytes and monocytes. However, role of these chemokines in tumorigenesis, especially with regard to interaction between tumor and its microenvironment, has not been clearly elucidated. The purpose of this study was to analyze the co-operative role of CXCL8 and CXCL12 in the tumor-stromal interaction in pancreatic cancer (PaCa). Using enzyme-linked immunosorbent assay (ELISA) and reverse transcription polymerase chain reaction (RT-PCR), we initially confirmed the expression of ligands and receptors, respectively, of CXC-chemokines in PaCa and stromal cells. We examined the co-operative role of CXCL8 and CXCL12 in proliferation/invasion of PaCa and human umbilical vein endothelial cells (HUVECs), and in HUVEC tube-formations through tumor-stromal interaction by MTS, Matrigel invasion, and angiogenesis assays, respectively. We detected expression of CXCR4, but not CXCR2, in all PaCa cells and fibroblasts. PaCa cells secreted CXCL8, and fibroblast cells secreted CXCL12. CXCL8 production in PaCa was significantly enhanced by CXCL12, and CXCL12 production in fibroblasts was significantly enhanced by co-culturing with PaCa. CXCL8 enhanced proliferation/invasion of HUVECs but did not promote proliferation/invasion of PaCa. Both recombinant and PaCa-derived CXCL8 enhanced tube formation of HUVECs that were co-cultured with fibroblast cells. CXCL12 enhanced the proliferation/invasion of HUVECs and the invasion of PaCa cells but had no effect on tube formation of HUVEC. We showed that PaCa-derived CXCL8 and fibroblast-derived CXCL12 cooperatively induced angiogenesis in vitro by promoting HUVEC proliferation, invasion, and tube formation. Thus, corresponding receptors CXCR2 and CXCR4 are potential antiangiogenic and antimetastatic therapeutic targets in PaCa.

241 DIBUTYRYL CYCLIC AMP AND EGF-LIKE FACTORS SUPPORT IN VITRO MATURATION OF PORCINE OOCYTES IN A CHEMICALLY DEFINED MEDIUM WITHOUT GONADOTROPINS

Exposure of porcine oocyte–cumulus complexes (OCC) to gonadotropins induces meiotic resumption, but the details of this mechanism are still unknown. The present study was undertaken to examine combinational effects of EGF-like factors and dibutyryl cyclic AMP (dbcAMP) in a chemically defined medium on in vitro maturation (IVM) of porcine oocytes. The OCC were aspirated from 3- to 6-mm-diameter follicles of prepuberal ovaries and used in the current study. The basic culture medium was a chemically defined medium, Porcine Oocyte Medium (POM; Research Institute for the Functional Peptides, Yamagata, Japan). In the first experiment, various concentrations (0, 10, and 1000 ng mL–1) of EGF-like factors (EGF, amphiregulin, and betacellulin) were added to POM during an entire IVM period (44 h). In the second experiment, to determine the additive effect of EGF-like factors, each EGF-like factor with an effective concentration was combined with the others. In the last experiment, to examine the combined effect with dbcAMP, OCC were exposed to EGF (10 ng mL–1), amphiregulin (1000 ng mL–1), and dbcAMP (1 mm) during the first 20 h of IVM and then the culture was continued in the absence of EGF-like factors and dbcAMP. After culture, in all experiments, meiotic resumption and the progress of oocytes were examined after denuding, fixing, and staining. Statistical analyses was performed by ANOVA with a Bonferroni-Dunn post hoc test (significance, P < 0.05). In the first experiment, all treatments without supplementation with 10 ng mL–1 amphiregulin increased the incidence of oocytes maturing to the MII phase, as compared with controls (29.1 to 39.3% v. 11.1%, P < 0.05). In the second experiment, combinations with 2 kinds of EGF-like factor slightly (but not significantly) improved the percentage of oocytes at the MII stage (37.7 to 47.4%). In the last experiment, supplementation with 1 mm dbcAMP during the first 20 h of IVM, regardless of the presence of EGF-like factors, significantly increased the incidence of MII oocytes as compared with controls, whereas the incidence was the highest when 1 mm dbcAMP, 10 ng mL–1 EGF, and 1000 ng mL–1 amphiregulin were supplemented (75.5%). When those oocytes were cultured in a chemically defined medium after in vitro fertilization, the developmental competence of oocytes to the blastocyst stage (25.0%) was not different from oocytes matured in the presence of gonadotropins and dbcAMP during the first 20 h of IVM (17.3%). These observations indicate that supplementation of a chemically defined maturation medium with EGF-like factors and dbcAMP during the first 20 h of IVM can support the meiotic progress and developmental competence of porcine oocytes well. Currently, we are examining the developmental competence of those oocytes after embryo transfer. The results will be presented at the meeting. This study was supported by MAFF AgriBio1605.

219 APPLICATION OF A MICROFLUIDIC SPERM SORTER TO THE IN VITRO PRODUCTION OF PORCINE EMBRYOS

In porcine in vitro fertilization (IVF), polyspermy is a persistent obstacle to the efficient production of normal embryos. A microfluidic sperm sorter (MFSS; Strex Inc., Osaka, Japan) was developed to isolate motile human spermatozoa (from diluted semen by two laminar flows in the microchannel). The motile spermatozoa can gradually accumulate in a chamber of the MFSS. We previously reported that the monospermy rate was higher when oocytes were co-cultured with isolated spermatozoa in an MFSS for 5 min than when spermatozoa were co-cultured traditionally in drops for 8 h (P < 0.05; Reprod. Fertil. Dev. 20, 187 abst). The present study was undertaken to compare the effect of oocyte location within the MFSS chamber on early development after IVF in the MFSS. A sperm-rich fraction from Berkshire boars was diluted at 1 × 108 cells mL–1 with modified Modena solution containing 20% seminal fluid. In the first experiment, a diluted semen sample was flowed with modified TCM-199 containing 5 mm caffeine (mm199-caf) for 5 min at room temperature. Before flowing, porcine IVM oocytes were positioned in a part of the MFSS chamber where motile spermatozoa would accumulate with mm199-caf. After flowing for 5 min, those oocytes were cultured in caffeine-free mm199 for 8 h and then in a chemically defined medium (PZM-5) for 7 days. In the second experiment, denuded oocytes were co-cultured with isolated spermatozoa at several locations in the MFSS chamber, and the penetration and monospermy rates were estimated. The concentration of motile spermatozoa was also measured at each place in the MFSS chamber after isolation for 5 min. Statistical analyses of results based on 4 to 5 replicates were carried out by ANOVA and Fisher’s PLSD post hoc test (significance, P < 0.05). When IVM oocytes were co-cultured with spermatozoa gradually accumulated in the chamber of the MFSS for 5 min, the cleavage rate (83.7 ± 6.3% of 121 oocytes) was not different from that of control oocytes co-cultured with spermatozoa (5.7 × 105 cells mL–1) in 100-μL drops for 5 min (84.6 ± 6.6% of 126 oocytes). However, the blastocyst formation rate (38.2 ± 3.3%) was higher than for the controls (20.6 ± 6.8%; P < 0.05). After flowing for 5 min, the distance from the inflow opening of the MFSS chamber to the location of the oocytes did not affect the sperm penetration rate, but did affect the monospermy rate (14.0 ± 4.0% of 48 oocytes at the nearest position to 50.0 ± 5.6% of 43 oocytes at the furthest position; P < 0.05). After flowing for 5 min, the concentration of motile spermatozoa was also different at each location (57.5 ± 5.6 × 104 cells mL–1 at the nearest position to 0.8 ± 0.5 × 104 cells mL–1 at the furthest position; P < 0.05). These observations demonstrate that co-culturing oocytes with spermatozoa that gradually accumulated in the MFSS chamber improved the efficiency of blastocyst formation in the pig, whereas efficiency was affected by the position where oocytes were located in the chamber.

122 GLYCOSAMINOGLYCANS IMPROVE THE NUMBER OF BLASTOMERES IN ZONA-FREE RAT AND MOUSE EMBRYOS

In general, early mammalian embryos are enclosed by zona pellucida until the blastocyst stage. The possible role of zona pellucida could be to maintain the three-dimensional structure of cleaving embryos, as well as preventing blastomeres from attack by immune cells and miscellaneous germs. However, beneficial roles of the zona on early development of blastomeres are still unknown. The present study was undertaken to examine if the absence of zona pellucida of rat and mouse embryos at the 8-cell stage affected the early development to the blastocyst stage. Furthermore, we examined whether supplementation of culture medium with glycosaminoglycans, such as hyaluronic acid and heparan sulfate, improved the early development or not. In the first experiment, embryos at the 8-cell stage were collected from mated Wistar rats or ICR mice and then, directly or after removing zona pellucida by using acidity Tyrode’s solution, cultured in modified R1ECM or kSOM medium for 24 h in an atmosphere of 5% CO2 in air. Following culture, the incidence of blastocyst formation and the cell number of blastocysts were examined. In the second experiment, intact or zona-free 8-cell embryos were cultured in various concentration of hyaluronic acid (0, 65, 125, 250 μg mL–1) or heparin sulfate (0 or 15 μg mL–1) for 24 h. After culture, blastocyst formation and cell number of blastocyst were similarly examined. Statistical analyses was performed by one-way ANOVA with Bonferroni/Dunn’s post hoc test (significance, P < 0.05). All percentage data were subjected to arc-sine transformation before statistical analysis. Percentage of blastocyst formation and the mean cell number of the blastocyst were less when zona-free 8-cell rat and mouse embryos were cultured (72.1 ± 2.9% and 22.8 ± 0.7), as compared with control intact embryos (94.3 ± 3.5% and 30.6 ± 1.1). Supplementation with hyaluronic acid (250 μg mL–1) improved the blastocyst formation rate of rat embryos (86.4 ± 5.0%) and the cell number of blastocysts (28.8 ± 0.5) to the same level of zona-intact embryos. In mouse embryos, the same concentration of hyaluronic acid improved only the cell number of blastocysts (from 21.7 ± 0.7 to 28.9 ± 0.7) to the same level of zona-intact embryos (30.9 ± 0.7). When heparin sulfate was supplemented, the incidence of blastocyst formation of rat embryos did not improve, but the cell number of the blastocyst (31.1 ± 0.7) did improve to the similar level with zona-intact embryos (30.6 ± 1.1). These results indicate that the zona pellucida has a beneficial effect on the early development of rat and mouse embryos and suggest that glycosaminoglycans, such as hyaluronic acid and heparan sulfate, contribute to the beneficial effect.

Loss of PTEN expression is associated with colorectal cancer liver metastasis and poor patient survival

BACKGROUND

The tumour suppressor phosphatase and tensin homolog (PTEN) is an important negative regulator of cell-survival signaling. To evaluate the correlation between PTEN expression and clinicopathological characteristics of colorectal cancer patients with and without liver metastases, we investigated PTEN expression in primary colorectal cancer and colorectal cancer liver metastases.

METHODS

Sixty-nine pairs of primary colorectal cancer and corresponding liver metastasis specimens were analyzed immunohistochemically, and the correlation between immunohistochemical findings and clinicopathological factors was investigated. Seventy primary colorectal cancer specimens from patients without liver metastases were used as controls.

RESULTS

PTEN was strongly expressed in 44 (62.9%) colorectal cancer specimens from patients without liver metastases. In contrast, PTEN was weakly expressed in 52 (75.4%) primary colorectal cancer specimens from patients with liver metastases, and was absent in liver metastases. Weak PTEN expression in colorectal cancer tissues was significantly associated with advanced TNM stage (p < 0.01) and lymph node metastasis (p < 0.05). PTEN expression was significantly stronger in primary colorectal cancer specimens from patients without liver metastases. Furthermore, among colorectal cancer patients with liver metastases, the 5-year survival rate was significantly higher in patients with positive PTEN expression compared to those with negative PTEN expression (p = 0.012).

CONCLUSION

Our results suggest that loss of PTEN expression is involved with colorectal cancer aggressive capacity and that diagnostic evaluation of PTEN expression may provide valuable prognostic information to aid treatment strategies for colorectal cancer patients.

Expression analysis of the prostaglandin E2 production pathway in human pancreatic cancers

OBJECTIVES

There is strong evidence for an important role of cyclooxygenase (COX) 2 and COX-2-generated PGE2 during pancreatic tumorigenesis. Cyclooxygenase 2 has therefore become a potential chemotherapeutic target for pancreatic cancer. However, recent studies raised concerns regarding the safety of selective COX-2 inhibitors. Although the benefits of COX-2 inhibition may eventually outweigh the associated cardiovascular risks, there are a number of alternative targets for inhibiting the formation of PGE2 in human tumors that may prove less harmful to the patient. This study aimed at analyzing the expression of various proteins involved in the generation of PGE2 in human pancreatic cancers.

METHODS AND RESULTS

Real-time polymerase chain reaction and Western blot analyses demonstrated overexpression of cytoplasmic phospholipase A2, COX-2, cytoplasmic prostaglandin E synthase, and microsomal prostaglandin E synthases 1 and 2 in most human pancreatic cancers when compared with matched normal pancreas. Immunohistochemistry revealed expression of these proteins predominantly by pancreatic cancer cells. Variable expression of these proteins was also confirmed in several human pancreatic cancer cell lines.

CONCLUSIONS

Our studies demonstrated for the first time that various proteins involved in the generation of PGE2 are overexpressed in human pancreatic cancers. These proteins may represent potentially novel targets for the therapy of pancreatic cancers.

Granulocyte-colony stimulating factor producing rectal cancer

Background

Granulocyte-colony stimulating factor (G-CSF)-producing cancer has been reported to occur in various organs, especially the lung. However, G-CSF-producing colorectal cancer (CRC) has never been reported in the English literature.

Case presentation

A 57-year-old man was admitted for the surgical removal of a rectal cancer. Some hepatic tumors in the liver were revealed concurrently, and their appearance suggested multiple liver metastases. Low anterior resection was performed. with the help of histopathological examination and immunohistochemical studies, we diagnosed this case to be an undifferentiated carcinoma of the rectum. After the operation, the white blood cell (WBC) count increased gradually to 81,000 cells/μL. Modified-FOLFOX6 therapy was initiated to treat the liver metastases, but there was no effect, and peritoneal dissemination had also occurred. The serum level of G-CSF was elevated to 840 pg/mL (normal range, <18.1 pg/mL). Furthermore, immunohistochemistry with a specific monoclonal antibody against G-CSF was positive; therefore, we diagnosed this tumor as a G-CSF-producing cancer. The patient died from rapid growth of the liver metastases and peritoneal dissemination 2 months after surgery.

Conclusion

This is the first case of G-CSF-producing rectal cancer, and its prognosis was very poor.

Opposing effects of n-6 and n-3 polyunsaturated fatty acids on pancreatic cancer growth

OBJECTIVES

Epidemiologic studies suggest that fish oil, rich in n-3 polyunsaturated fatty acids (PUFA), possesses antitumor activity, whereas n-6 PUFAs may stimulate the development of cancers. The aim of this study was to evaluate the effects of n-6 and n-3 PUFAs on the growth of pancreatic cancer.

METHODS

The n-6 PUFA arachidonic acid (AA) stimulated the growth of cyclooxygenase (COX) 2 positive human pancreatic cancer (PaCa) cells, which was mediated by COX-2 generated prostaglandin E2 (PGE2) binding to EP2 and EP4 receptors. In contrast, the n-3 PUFA eicosapentaenoic acid decreased the growth of COX-2-positive and COX-2-negative PaCa cells. The COX-2-dependent mechanism of eicosapentaenoic acid was mediated by binding of PGE3 to EP2 and EP4 receptors. Dietary intake of n-3 PUFAs decreased the growth of pancreatic cancers in a xenograft model, which was accompanied by a decrease of PGE2 and an increase of PGE3 in the tumors.

CONCLUSIONS

Our studies provide evidence that n-3 PUFAs possess antitumor activities, whereas n-6 PUFAs stimulate pancreatic tumor growth. The opposite effects of n-3 and n-6 PUFAs are mediated by the formation of different prostaglandin species. n-3 PUFAs may prove beneficial as monotherapy or combination therapy with standard chemotherapeutic agents in pancreatic cancer patients.

73 SUPPLEMENTATION OF FROZEN BOAR SEMEN WITH β-MERCAPTOETHANOL INCREASES THE INCIDENCE OF INTACT CELLS AFTER THAWING

During the process of freezing and thawing of boar spermatozoa, a large number of the cells appear to be injured by some stresses such as osmotic forces and oxidation, causing reduced viability and penetrability. β-Mercaptoethanol (bME), a strong reducing agent, may ease oxidative stress and rescue sperm cells from those injuries. The aim of this study was to determine the effect of the presence of bME during freezing and thawing of boar spermatozoa on the viability and acrosome status of the sperm cells. Semen samples were collected from 3 boars; only samples with a high motility (more than 80%) were used for this experiment. Each sample was diluted 1:1 with modified Modena solution and kept overnight at 15�C. After centrifugation at 800g for 10 min, the diluent supernatant was removed; spermatozoa were re-suspended at 2 � 109 cells mL–1 in the first diluent (8.8% trehalose solution containing 20% egg yolk and antibiotic) supplemented with 0, 25, or 50 µm bME, and then cooled to 5�C over 2–3 h. At 5�C, semen samples were further diluted 1:1 with the second diluent (same as the first diluent + 5% glycerin + 1.48% Orvus ES Paste (Equex STM; Minitube, Verona, WI, USA)) supplemented with 0, 25, and 50 µm bME, respectively. After packaging the semen into 0.5-mL straws, it was frozen by keeping the straws 4 cm above the surface of liquid nitrogen for 15 min and then storing them in liquid nitrogen until use. After thawing at 37�C for 30 s, semen samples were re-suspended in 10 mL of BTS solution containing 1.15 mm caffeine and 4 mm Ca chloride, and incubated at 37�C under 5% CO2 in air for 90 min. Viability, DNA fragmentation, and acrosome status of spermatozoa were assessed by flow cytometry after staining with SYBR�14/PI (Molecular Probes, Inc., Eugene, OR, USA), acridine orange, and PNA/PI, respectively. Statistical analyses of data from at least 3 replicated trials were carried out by ANOVA and Fisher's protected least-squares difference (PLSD) post-hoc test. Just after thawing, no differences in viability (45.6–51.1%; P = 0.67), DNA fragmentation (0.7–0.9%; P = 0.76), and acrosome status (intact acrosome: 79.2–83.0%; P = 0.26) of the spermatozoa were observed when sperm cells were frozen and thawed in 0, 25, and 50 µm bME. After culture for 90 min, however, the incidence of spermatozoa with an intact acrosome was significantly higher (P < 0.05) when the semen was frozen and thawed in the presence of 50 µm bME (70.9%), compared with 0 (61.7%) and 25 µm bME (61.0%). Chlortetracycline (CTC) analyses were peformed to confirm that the incidence of intact spermatozoa was higher (P < 0.01) in 50 µm bME (67.6%) than that of non-supplementation controls (51.4%). These results demonstrate that supplementation of semen with 50 µm bME during freezing and thawing processes reduces acrosome damage of boar spermatozoa.

Basement Membrane Proteins Play an Important Role in the Invasive Processes of Human Pancreatic Cancer Cells

BACKGROUND

The invasive interaction between cells and their matrix has important roles in tumor cell invasion. This study investigated modulation of basement membrane (BM) proteins, especially collagen IV (Coll IV), laminin, and fibronectin (FN), in invasion of human pancreatic cancer cells. Furthermore, we examined the roles of beta(1)-integrins and arginine-glycine-aspartic (RGD)-containing oligopeptide in cell-matrix interactions.

MATERIALS AND METHODS

Expression of integrins were examined by reverse transcriptase-polymerase chain reaction and flow-cytometric analysis in three human pancreatic cancer cell lines (BxPC-3, PANC-1, and SW1990), respectively. To determine the effect of BM proteins, invasion assays were performed. Western blot analysis for extracellular signal-regulated kinase (ERK) was performed to investigate the involvement of ERK1/2 signaling pathways.

RESULTS

BM proteins significantly enhanced the invasive behavior of pancreatic cancer cells. Pretreatment with anti-beta(1)-integrin antibody suppressed invasion into Matrigel, but RGD-containing peptide inhibited invasion, which was enhanced by Coll IV and FN, not laminin. Treatment with both RGD-containing peptide and beta(1)-integrin antibody inhibited ERK1/2 phosphorylation activated by Coll IV and FN.

CONCLUSIONS

BM proteins have positive actions on the processes of pancreatic cancer cell invasion and cross-talk between BM proteins and beta(1)-integrins widely participates in the multistep processes of pancreatic cancer invasion and metastasis formation.

215 APPLICATION OFA MICROFLUIDIC SPERM SORTER TO THE IN VITRO FERTILIZATION OF PORCINE OOCYTES

In porcine IVF, polyspermy is a persistent obstacle to the efficient production of normal embryos in vitro. A microfluidic sperm sorter (MFSS; Strex Inc., Osaka, Japan) has been developed to isolate motile human spermatozoa (from diluted semen by 2 laminar flows in the microchannel). The motile spermatozoa can gradually accumulate in a chamber of the MFSS. In addition, we have succeeded in reducing the incidence of polyspermic penetration by a transient coincubation of oocytes with spermatozoa in the presence of caffeine, followed by culture of the oocytes in the absence of caffeine (2004 Reproduction 128, 789–800). If porcine oocytes could be cocultured with motile spermatozoa in the chamber of the MFSS, the gradual accumulation of motile spermatozoa might further improve the efficiency of production of monospermic fertilized porcine embryos. The current study was undertaken to apply the MFSS technology to porcine IVF. The sperm-rich fraction from 3 Berkshire boars was diluted at 1 � 108 cells mL–1 with modified Modena containing 20% seminal fluid, cooled to 15�C for 4 h, and kept at the same temperature until use within 2 days. Stored, diluted semen with greater than 80% viability was flowed with Tyrode lactate-HEPES-polyvinyl alcohol medium for 5 or 10 min at room temperature. The concentration and viability of spermatozoa mixed in the flowed medium were determined. In the next experiment, a diluted semen sample was flowed with modified TCM-199 containing 5 mm caffeine for 5 min at room temperature. Before flowing, porcine IVM oocytes were put into the chamber of the MFSS, where motile spermatozoa will accumulate with modified TCM-199 containing 5 mm caffeine. After flowing for 5 min, those oocytes were transferred into a 500-µL droplet of caffeine-free modified TCM-199, and culture was continued for 8 h. Statistical analyses were carried out by ANOVA and Fisher's PLSD post hoc test. After flowing for 5 min, the concentration of spermatozoa recollected from the chamber was 5.7 � 105 cells mL–1. The viability of recollected spermatozoa was significantly higher than the original flowed semen. However, when spermatozoa were flowed for 10 min, the viability of recollected spermatozoa was not different from the original flowed semen, whereas the concentration of recollected spermatozoa was 9.7 � 105 cells mL–1. When IVM oocytes were cocultured with spermatozoa gradually accumulated in the chamber of MFSS for 5 min, 35% (22 to 48%) of oocytes were penetrated, and 95% (90 to 100%) of the penetrated oocytes were monospermic. These observations demonstrate that the MFSS can separate penetrable boar spermatozoa with a high viability and sufficient concentration for IVF. Furthermore, the current data suggest the possibility of improving the efficiency of monospermic fertilization of porcine IVM oocytes by a transient coculture with MFSS.

243 NUCLEOSIDES REDUCE THE POTENTIAL OF THE MITOCHONDRIAL INNER MEMBRANE AND THE DEVELOPMENTAL COMPETENCE OF MOUSE OOCYTES DURING IN VITRO MATURATION

Although nucleosides such as adenosine exist in follicular fluid and decrease during oocyte maturation (Eppig et al. 1985 Biol. Reprod. 33, 1041–1049), the role of nucleosides is still unclear. The present study was undertaken to determine the effect of nucleoside on nuclear and cytoplasmic maturation of mouse oocytes. Oocyte–cumulus complexes (OCCs)were collected from the large antral follicles of C57BL/6J female mice (3–5 weeks old) 4 h after a combination injection of equine chorionic gonadotropin (eCG) and hCG with a 48-h interval, and cultured in maturation medium (αMEM containing 3 mg mL–1 BSA, 0.23 mm Na pyruvate and antibiotics) with or without ribo- and deoxyribo-nucleosides (10–11 µg mL–1) for 12 h. Statistical analyses in this study were carried out by ANOVA and Bonferroni/Dunn's post hoc test. Regardless of the presence of nucleosides, a majority of oocytes developed to the metaphase-II stage in vitro, and the incidence was not different with in vivo-matured oocytes. However, the mitochondrial membrane potential (MMP) of oocytes was significantly lower when the oocytes were matured in the presence of nucleosides, as compared with nucleoside-free controls. In the scanning experiment of MMP level during in vitro maturation (IVM), the MMP of oocytes maturing in vivo increased between 8 and 12 h after hCG injection, whereas no rises of MMP was observed in oocytes matured in vitro in the presence of nucleosides. To examine the affecting period of nucleosides, OCCs were cultured for the first 4 h or the latter 8 h of IVM in the presence of nucleosides. MMP of the oocytes was significantly lower only when the OCCs were exposed to nucleosides for the latter 8 h of IVM. To determine if adenosine in the nucleosides (10 µg mL–1) affects the MMP of oocytes, OCCs were exposed to adenosine or a mixture of guanosine, cytidine, and uridine during the latter 8 h of IVM. The MMP of oocytes exposed to adenosine was lower than that of in vivo-matured oocytes and of oocytes exposed to a mixture of guanosine, cytidine, and uridine. To determine the effect of nucleosides on the developmental competence, oocytes exposed to adenosine during the latter 8 h of IVM were cultured in kSOMaa containing 1 mg mL–1 BSA after activation in the presence of 10 mm SrCl2 and 5 µg mL–1 cytochalasin B for 6 h. Pronuclear formation and early development of those were compared with artificially activated oocytes matured in vivo or in the absence of nucleosides. The incidences of pronuclear formation and cleavage of oocytes matured in the presence of adenosine following activation were extremely decreased, as compared with control oocytes matured in vivo or in the absence of adenosine. These observations indicate that nucleosides, at least adenosine, inhibit an increase of MMP of oocytes during the latter half of meiotic maturation, and detrimentally affect the developmental competence of murine oocytes.

Complete extragastric growth in a giant gastrointestinal stromal tumor: report of a case

Gastrointestinal stromal tumors (GISTs) are characterized by remarkable variability in their differentiation potential, but most of these lesions do not display convincing smooth muscle or neuronal differentiation. Here we report the case of a 65-year-old woman who underwent a perfect resection of a large submucosal tumor that displayed extragastric growth. The specimen was revealed to be an elastic soft tumor, 18 x 25 x 11 cm in size. Histologically, the tumor consisted of spindle-shaped cells, with a mitotic rate of 12 per 10 high-power fields. Immunohistochemically, the tumor showed positive staining for CD34 and c-kit but negative staining for alpha-smooth muscle actin, Desmin, and s-100 protein. From these findings, the tumor was diagnosed as an uncommitted type of GIST with high-grade malignancy. This case needs careful and long-term follow-up to monitor for signs of local recurrence or distant metastasis.

Synthetic serine protease inhibitor, gabexate mesilate, prevents nuclear factor-kappaB activation and increases TNF-alpha-mediated apoptosis in human pancreatic cancer cells

Gabexate mesilate (GM), a synthetic serine protease inhibitor, suppresses nuclear factor-kappaB (NF-kappaB) activity in human monocytes or human umbilical vein endothelial cells (HUVECs). In this study we examine whether GM also suppresses NF-kappaB activation and induces apoptosis in human pancreatic cancer cell lines. The addition of tumor necrosis factor alpha (TNF-alpha) did not change the rates of growth of BxPC-3 and MIA PaCa-2. However, in the presence of GM and TNF-alpha, proliferation decreased in a dose-dependent manner. GM- and TNF-alpha-treated cells exhibited morphologic changes indicative of apoptosis, including chromatin condensation and nuclear fragmentation. The NF-kappaB activity of both cell lines was increased by the addition of TNF-alpha, while TNF-alpha-induced NF-kappaB activity was suppressed by prestimulation with GM in a dose-dependent manner. Caspase 3 and 7 activity was significantly increased by TNF-alpha with GM stimulation. Furthermore, GM also suppressed the invasive potential of both cell lines. These results indicate that GM inhibits TNF-alpha-induced NF-kappaB activation and enhances apoptosis in human pancreatic cancer cell lines.

Interleukin-1alpha enhances angiogenesis and is associated with liver metastatic potential in human gastric cancer cell lines

BACKGROUND

To better understand the underlying mechanism of liver metastasis formation in human gastric cancer, we evaluated the angiogenic capabilities of human gastric cancer cell lines with different metastatic potentials as well as the role of interleukin (IL)-1alpha in the angiogenic process.

MATERIALS AND METHODS

Reverse transcription-polymerase chain reaction was used to detect the expression of IL-1alpha and vascular endothelial growth factor (VEGF) mRNA in gastric cancer cell lines with different liver metastatic potentials. Levels of VEGF secreted by human gastric cancer cells were measured by enzyme-linked immunosorbent assay. We also examined how gastric cancer cells with different metastatic potentials influence the proliferation and tube formation of human umbilical vein endothelial cells (HUVECs) using the Premix WST-1 cell proliferation assay system and an angiogenesis assay, respectively.

RESULTS

IL-1alpha expression levels were significantly correlated with liver metastatic potential in gastric cancer cell lines. Levels of VEGF secreted by gastric cancer cells appear to be regulated by IL-1alpha through IL-1 receptor Type 1 and were correlated with liver metastatic potential. Both HUVEC proliferation and tube formation were strongly enhanced by coculture with high liver-metastatic gastric cancer cells and were enhanced to a similar extent by culture in the presence of IL-1alpha. In contrast, blockade of IL-1alpha inhibited both HUVEC proliferation and angiogenesis.

CONCLUSIONS

IL-1alpha may play a role in liver metastasis of gastric cancer via enhanced vascular endothelial cell proliferation and angiogenesis.

Stem cell factor/c-kit receptor signaling enhances the proliferation and invasion of colorectal cancer cells through the PI3K/Akt pathway

In this study, we examined the role of c-kit receptor (KIT) signal transduction on the proliferation and invasion of colorectal cancer cells. We found that c-kit was expressed in 2 colorectal cancer cell lines as determined by RT-PCR, Western blot, and flow cytometry. In KIT-positive lines, KIT was activated by stem cell factor (SCF). SCF enhanced cellular proliferation of positive lines as demonstrated by the WST-1 proliferation assay. Furthermore, SCF enhanced the invasive ability of KIT-positive cell lines. SCF stimulation upregulated p44/42 mitogen-activated protein kinase (MAPK) and Akt as shown by Western blot. We examined the roles played by p44/42 MAPK and phosphatidylinositol 3-kinase (PI3K)/Akt pathways in proliferation and invasion. PI3K/Akt activity strongly correlated with proliferation and invasion and p44/42 MAPK was correlated with only invasion. In conclusion, the SCF-enhanced proliferation and invasion of KIT-positive colorectal cancer cells is achieved mainly through the PI3K/Akt pathway.

Delayed progression of pancreatic intraepithelial neoplasia in a conditional Kras(G12D) mouse model by a selective cyclooxygenase-2 inhibitor

Pancreatic ductal adenocarcinomas are thought to arise from noninvasive, intraductal precursor lesions called pancreatic intraepithelial neoplasias (PanIN). The study of PanINs holds great promise for the identification of early detection markers and effective cancer-preventing strategies. Cyclooxygenase-2 (COX-2) represents an intriguing target for therapeutic and preventive approaches in various human malignancies. The aim of the present study was to evaluate the efficacy of a selective COX-2 inhibitor to prevent the progression of PanINs in a conditional Kras(G12D) mouse model. Offspring of LSL-KRAS(G12D) x PDX-1-Cre intercrosses were randomly allocated to a diet supplemented with the selective COX-2 inhibitor nimesulide (400 ppm) or a control diet. After 10 months, animals were sacrificed. Successful recombination in the pancreas was evaluated by PCR. The pancreas of KRAS(G12D);PDX-1-Cre mice was analyzed for the presence of murine PanINs. Animals fed the COX-2 inhibitor had significantly fewer PanIN-2 and PanIN-3 lesions than control animals (P < 0.05). Ten percent of all pancreatic ducts in the nimesulide-fed animals showed PanIN-2 or PanIN-3 lesions, whereas 40% of the pancreatic ducts in the control animals had PanIN-2 or PanIN-3 lesions. Intrapancreatic prostaglandin E(2) levels were reduced in nimesulide-fed animals. Immunohistochemistry confirmed COX-2 expression in early and late PanINs. In summary, we found that the selective COX-2 inhibitor nimesulide delays the progression of pancreatic cancer precursor lesions in a preclinical animal model. These data highlight the importance of COX-2 in the development of pancreatic cancer. Inhibition of COX-2 may represent an intriguing strategy to prevent pancreatic cancer in high-risk patients.

Successful paclitaxel-based chemotherapy for an alpha-fetoprotein-producing gastric cancer patient with multiple liver metastases

Background

Alpha-fetoprotein (AFP)-producing gastric cancer is known to frequently cause multiple liver metastases and to have an extremely poor prognosis.

Case presentation

A 64-year-old Japanese man admitted to our hospital was diagnosed with gastric cancer with liver metastases. He underwent a total gastrectomy with splenectomy, and pathological stage IV disease according to the classification proposed by the Japanese Gastric Cancer Association was assigned. The histological diagnosis was poorly differentiated adenocarcinoma, and tumor production of AFP was confirmed by immunohistochemical staining. Following surgery, the patient received combination chemotherapy consisting of TS-1 and paclitaxel. Initially, AFP levels decreased dramatically and computed tomography (CT) revealed regression of liver metastases. However, multiple new liver metastases appeared and serum AFP levels increased after 5 months. A regimen of 5-FU plus paclitaxel followed by paclitaxel monotherapy was used next. Serum AFP levels once again decreased and CT showed regression or disappearance of liver metastases. The patient currently has a very good quality of life, and is receiving weekly paclitaxel monotherapy as an outpatient. No progression of liver metastases has been observed to date.

Conclusion

We consider this rare case to have significant value with respect to treatment of AFP-producing gastric cancer with multiple liver metastases, and propose that combining surgery with chemotherapeutic agents such as paclitaxel may lead to a better prognosis in such cases.

Antiproteases in preventing the invasive potential of pancreatic cancer cells

The process of tumor progression and metastasis involves degradation of the extracellular matrix and is governed by an intricate balance of proteases, their activators and their inhibitors, in which malignant cells are permitted to infiltrate the adjacent structures and gain access to lymph and blood vessels. These proteases can be broadly categorized into three families: matrix metalloproteinases, serine proteinases and cysteine proteinases, all of which have all been implicated in these processes. The presence of neural invasion is often considered to be a poor prognostic sign; however, the cellular mechanisms underlying this propensity for perineural invasion are unknown. We recently researched the relationship between the glial cell line-derived neurotrophic factor and perineural invasion by human pancreatic cancer cells. We also confirmed that NF-kappa B is a part of the signaling pathway from the glial cell line-derived neurotrophic factor in human pancreatic cancer cells, and documented the inhibitory effect of gabexate mesilate, a well-known non-physiological synthetic serine protease inhibitor, for pancreatic cancer invasion. Recent studies on the role of proteases and protease inhibitors in pancreatic cancer invasion are also reviewed.