Phosphoinositide 3-kinase inhibitor (wortmannin) inhibits pancreatic cancer cell motility and migration induced by hyaluronan in vitro and peritoneal metastasis in vivo.

In order to block peritoneal metastasis of pancreatic cancer cells, we have attempted to block the signal transduction pathway involving hyaluronan (HA), Src, phosphoinositide 3-kinase (PI3K) and Akt. We examined the effects of Src, PI3K and Akt inhibitors on pancreatic cancer cell motility, invasion and metastasis. The pancreatic cancer cell line SW1990, known to cause peritoneal metastasis efficiently in nude mice, was used in this study. SW1990 cells were stimulated by HA to induce Akt phosphorylation. Then, the inhibitory effects of PI3K and Src kinase inhibitors were examined. Cell motility and cell migration assays were adopted to assess the cancer cell motility and its migration capability. We also examined the therapeutic efficacies of PI3K inhibitor wortmannin on peritoneal metastasis of SW1990 cells in the nude mouse model. Stimulation of SW1990 cells by HA markedly induced the Src-PI3K-Akt signaling, thus enhancing cancer cell motility and its migration. Significantly, we found that wortmannin could exert marked inhibition of the peritoneal metastasis of SW1990 in nude mice in vivo. These findings indicate that the PI3K-Akt signaling pathway plays an essential role in peritoneal metastasis and PI3K inhibitors such as wortmannin can be novel modalities to prevent peritoneal metastasis of invasive cancers such as pancreatic cancer.

Interleukin-2 potentiation of cetuximab antitumor activity for epidermal growth factor receptor-overexpressing gastric cancer xenografts through antibody-dependent cellular cytotoxicity.

Cetuximab, a chimeric monoclonal antibody to epidermal growth factor receptor (EGFR), has been proved to have clinically significant antitumor activity against advanced colorectal cancers, but its therapeutic activity for gastric cancers remains unclear. In the present study, we investigated the antitumor effect and action mechanism of cetuximab using EGFR high-expressing (MKN-28) and EGFR low-expressing (GLM-1) gastric cancer cell lines without gene amplification. Cetuximab showed neither significant growth inhibition nor induction of apoptosis in either cell line in vitro, and only slightly inhibited ligand-induced phosphorylation of protein kinase B and extracellular signal-regulated kinase in MKN-28 cells. In contrast, cetuximab significantly inhibited subcutaneous and intraperitoneal tumor growth of MKN-28 cells, but not GLM-1 cells, in nude mice. This antitumor activity was significantly enhanced and diminished in nude mice by treatment with interleukin-2 (IL-2) and antiasialo GM1 antibody, which can expand and deplete natural killer (NK) cells, respectively. Antibody-dependent cellular cytotoxicity (ADCC) of cetuximab, as measured by (51)Cr release assay, was significantly higher in MKN-28 than in GLM-1 cells. This ADCC activity was enhanced by IL-2 and reduced by heat-aggregate of human immunoglobulin G, an inhibitor for FcR-III of NK cells. These results suggest that cetuximab in combination with IL-2 shows significant antitumor activity against EGFR high-expressing gastric cancer mainly through NK cell-mediated ADCC. Combination therapy with cetuximab and IL-2 would thus offer a new potential therapeutic approach for a subset of EGFR-overexpressing gastric cancers.

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.

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.

Posterior mediastinal angioleiomyoma: report of a case.

We describe a case of mediastinal angioleiomyoma in an asymptomatic 72-year-old man, who was admitted to our hospital for a mediastinal tumor discovered during an annual medical examination. The tumor was evaluated by computed tomography (CT) and magnetic resonance imaging (MRI). Unenhanced CT scans demonstrated a tumor that was adjacent to the descending aorta. The tumor was partially enhanced in the early phase of contrast-enhanced CT, and in the late phase there was additional tumor enhancement. With MRI, the tumor displayed a homogeneous low signal intensity on the T1-weighted image and a homogeneous very high signal intensity on the T2-weighted image. Contrast-enhanced MRI demonstrated the same enhancement pattern as CT. The examination results led to a preoperative diagnosis of posterior mediastinal hemangioma, and the patient underwent surgery. The tumor originated from the supreme intercostal vein, and was diagnosed as an angioleiomyoma by histopathologic examination. Because mediastinal angioleiomyomas are very rare, they are difficult to diagnose preoperatively. However, we believe that CT and MRI can be of significant help in the differential diagnosis.

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.

Effects of Helicobacter pylori infection on human pancreatic cancer cell line.

BACKGROUND/AIMS: Helicobacter species has been shown to be commonly present in extragastric human organs by polymerase chain reaction (PCR). To date, a few studies have reported that infection by Helicobacter pylori (H. pylori) was a risk factor for pancreatic malignancies, but this was not investigated very well. Therefore, we examined effects of H. pylori infection on human pancreatic cancer cells. METHODOLOGY: Interleukin (IL)-8 and vascular endothelial growth factor (VEGF) secretions by human pancreatic cancer cells which were co-cultured with H. pylori, were measured by enzyme-linked immunosorbent assay (ELISA). We then examined whether activities of proliferation factors nuclear factor-kappaB (NF-kappaB), activator protein-1 (AP-1), and serum response element (SRE) of human pancreatic cancer cells were increased by H. pylori infection. Furthermore, we examined cytotoxin-associated gene A protein (CagA) secretion into pancreatic cancer cells using Western blotting. RESULTS: IL-8 and VEGF secretion levels and activities of proliferation factors NF-kappaB, AP-1, and SRE of human pancreatic cells increased by H. pylori infection. Moreover, CagA secretion into pancreatic cancer cells was confirmed by Western blotting. CONCLUSIONS: Helicobacter pylori infection of human pancreatic cells may increase malignant potential of pancreatic cells, which seems to involve the same mechanisms as in gastric cancer cells.

Gastrointestinal stromal tumor of the rectum with liver metastasis: report of a case.

Gastrointestinal stromal tumors (GISTs) have unique immunohistochemical and molecular genetic features that set them apart from leiomyomas, leiomyosarcomas, and schwannomas. Although recurrence of GIST usually tends to develop locally or in the liver, rectal GIST reoccur predominantly at the original site of the tumor. We describe a rare case of rectal GIST with multiple liver metastases. We carried out immunohistochemical staining for p53 protein, proliferating cell nuclear antigen (PCNA), integrins, and interleukin-1 receptor type I (IL-1RI) in order to investigate the degree of malignancy of this neoplasm in addition to the immunohistochemical analyses that were necessary for diagnosing GIST. Histologically, the rectal tumor was classified as an uncommitted type of rectal GIST with multiple liver metastases. Positive immunostaining for PCNA, alpha6 integrin subunit, and IL-1RI was found in both the rectal and hepatic tumors. The patients with a rectal GIST may have an increased risk of liver metastasis and a poor prognosis independent of the size of the tumor.

The relationship between GDNF and integrins in human colorectal cancer cell activity.

BACKGROUND/AIMS: This study was performed to determine whether GDNF influences the expression of integrins in colorectal cancer cell lines and to elucidate the mechanisms of adhesion to and invasion of extracellular matrix (ECM) proteins. METHODOLOGY: The expression of integrin subunits and alteration of this expression by GDNF were examined by flow-cytometric analysis and cellular enzyme-linked immunosorbent assay in four human colorectal cancer cell lines. Assays to evaluate adhesion and invasion of cancer cells toward ECM proteins were conducted to investigate whether increased integrin expression affects the interaction between cancer cells and putative integrin ECM ligands. RESULTS: The RET/GFRalpha-1 receptor complex for GDNF was expressed in all four colorectal cancer cell lines. The expression of the Beta1 integrin subunit in these cells was significantly enhanced by GDNF. The enhancement and associated increase in adhesion and invasion abilities in response to by GDNF were inhibited by blocking the GDNF receptor or the integrin P1 subunit. CONCLUSIONS: In colorectal cancer, the enhancement of integrin expression by signaling through the GDNF receptor strongly influences adhesion to and invasion of ECM proteins.

[Bacteria isolated from surgical infections and its susceptibilities to antimicrobial agents--special references to bacteria isolated between april 2003 and march 2004].

Tendency of isolated bacteria from infections in abdominal surgery during the period from April 2005 to March 2006 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, 384 strains including 18 strains of Candida spp. were isolated from 161 (70.3%) of 229 patients with surgical infections. One hundred and ninty-five strains were isolated from primary infections, and 171 strains were isolated from postoperative infections. From primary infections, aerobic Gram-negative bacteria and aerobic Gram-positive bacteria were predominant, while aerobic Gram-positive bacteria were predominant from postoperative infections. The isolation rate of aerobic Gram-positive bacteria, such as Enterococcus spp. and Staphylococcus aureus were higher from both types of infections. Among anaerobic Gram-positive bacteria, the isolation rate of Peptostreptococcus spp. was the highest from both types of infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Pseudomonas aeruginosa, Klebsiella spp. in this order, and from postoperative infections, E. coli was the most predominantly isolated, followed by Klebsiella pneumoniae and P. aeruginosa. Among anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis group was the highest from both primary and postoperative infections. In this series, we noticed no vancomycin-resistant Gram-positive cocci, nor multidrug-resistant P. aeruginosa. But cefazolin-resistant E. coli producing extended spectrum fl-lactamase was seen in 5.0 per cents. We should be carefully followed up the facts that the increasing isolation rates of B. fragilis group and Bilophila wadsworthia which were resistant to both penicillins and cephems.

Interleukin-1alpha enhances the aggressive behavior of pancreatic cancer cells by regulating the alpha6beta1-integrin and urokinase plasminogen activator receptor expression.

BACKGROUND: In human pancreatic cancer progression, the alpha6beta1-integrin is expressed on cancer cell surface during invasion and metastasis formation. In this study, we investigated whether interleukin (IL)-1alpha induces the alterations of integrin subunits and urokinase plasminogen activator/urokinase plasminogen activator receptor (uPA/uPAR) expression in pancreatic cancer cells. We hypothesize that the alterations of integrin subunits and uPA/uPAR expression make an important role in signaling pathways responsible for biological behavior of pancreatic cancer cells. RESULTS: IL-1alpha upregulated the expression of alpha6 and beta1 integrins without any alterations of alpha5 and alphav integrins expression. IL-1alpha also induced enhancement in the expression of uPA/uPAR in pancreatic cancer cells. IL-1alpha enhanced the proliferation, adhesion, and migration in pancreatic cancer cells, and IL-1alpha-induced alterations of uPA/uPAR expression correlated with the increased the migration of pancreatic cancer cells. Upregulation of alpha6 integrin subunit and uPA/uPAR correlated with the activation of Ras and downstream extracellular signal-regulated kinase (ERK) pathways. IL-1alpha-induced activation of Ras and downstream ERK can be inhibited by using inhibitory antibodies against alpha6 and beta1 integrin and uPAR, consistent with the inhibition of proliferation, adhesion and migration of pancreatic cancer cells. Immunohistochemical analysis demonstrated a significant association between strong expressions of alpha6 integrin with uPAR in pancreatic cancer specimens. Furthermore, the strong expression of alpha6 integrin and uPAR was found to be independent prognosticator in pancreatic cancer patients. CONCLUSION: Based on these findings, we conclude that IL-1alpha can induce selective upregulation of alpha6beta1-integrin and uPA/uPAR in pancreatic cancer cells and these changes may modulate the aggressive functions of pancreatic cancer.

The stem cell factor/c-kit receptor pathway enhances proliferation and invasion of pancreatic cancer cells.

BACKGROUND: The transmembrane protein c-kit is a receptor tyrosine kinase (KIT) and KIT is expressed in solid tumors and hematological malignancies such as gastrointestinal stromal tumor (GIST), small-cell lung cancer and chronic myelogenous leukemia (CML). KIT plays a critical role in cell proliferation and differentiation and represents a logical therapeutic target in GIST and CML. In pancreatic cancer, c-kit expression has been observed by immunohistochemical techniques. In this study, we examined the influence of c-kit expression on proliferation and invasion using five pancreatic cancer cell lines. In addition, the inhibitory effect of imatinib mesylate on stem cell factor (SCF)-induced proliferation and invasion was evaluated. Finally, we also analyzed KIT and SCF expression in pancreatic cancer tissues using immunohistochemistry and correlated the results with clinical features. RESULTS: RT-PCR revealed that two pancreatic cancer cell lines, PANC-1 and SW1990, expressed c-kit mRNA. By Western blot analysis, c-kit protein was also present in those lines. In KIT-positive pancreatic cancer cell lines, proliferation and invasion were significantly enhanced by addition of SCF. In contrast, SCF did not enhance proliferation and invasion in the three KIT-negative lines (BxPC-3, Capan-2 and MIA PaCa-2). 5 muM imatinib mesylate significantly inhibited SCF-enhanced proliferation to the same extent compared with the control. Similarly, SCF-enhanced invasive ability was significantly inhibited by 5 muM imatinib mesylate. KIT was expressed in 16 of 42 clinical specimens by immunohistochemistry, and KIT expression was significantly related to venous system invasion. Furthermore, patients expressing both KIT and SCF had a somewhat lower survival. CONCLUSION: Our results demonstrated that the SCF-KIT pathway enhanced the proliferation and invasiveness in KIT-positive pancreatic cancer cell lines and that the enhanced proliferation and invasion were inhibited by imatinib mesylate. We propose that inhibitors of c-kit tyrosine kinase receptor have the potential to slow the progression of KIT-positive pancreatic cancers.

Reactive lymphoid hyperplasia of the liver in a patient with colon cancer: report of two cases.

BACKGROUND: Reactive lymphoid hyperplasia (RLH) of the liver is very rarely reported, and we encountered two cases of RLH of the liver in a patient with colon cancer. CASE PRESENTATION: In the first case, a 77-year-old woman was admitted for the surgical removal of a ascending colon cancer. A hepatic tumor in the left lobe was concurrently revealed by computed tomography (CT), and magnetic resonance imaging (MRI). The appearance suggested liver metastasis. Right hemicolectomy and partial hepatectomy were performed. On histopathological examination, lymphoid follicles with germinal centers were seen in the tumor-like lesion, and remarkable lymphoid infiltration with germinal centers was seen in the portal area around the nodule. Immunohistochemical studies revealed polyclonality of infiltrating lymphocyte. Consequently, this nodular lesion was diagnosed as RLH of the liver. In the second case, a 64-year-old woman who had a radical right hemicolectomy for stage II ascending colon cancer 10 years ago was admitted with dysuria. A hepatic tumor in the left lobe was concurrently revealed by CT and MRI, suggesting hepatocellular carcinoma. A left lateral segmentectomy was performed. Microscopically, this lesion revealed the almost same findings as the first case, so this nodular lesion was diagnosed as RLH of the liver. CONCLUSION: Our two cases were the first report of RLH of the liver accompanying colon cancer. Because there are a very few cases, so it is not clear whether the malignancies were involved in the onset of RLH. But we believe that new factors involved in the onset mechanism of RLH may be identified by carefully monitoring the clinical course of our two patients.

Treatment of peritoneal carcinomatosis using carboplatin-loaded hydroxyapatite particles.

UNLABELLED: The anti-tumor effects and tissue distribution of carboplatin (CBDCA) incorporated into hydroxyapatite (HAP) particles was studied. MATERIALS AND METHODS: Seven days after the intraperitoneal (i.p.) implantation of AH130 tumor cells into Donryu rats, the animals were randomized into four groups: group I was treated with saline i.p.; Group II, with CBDCA i.v.; group III with CBDCA i.p.; and group IV with HAP-CBDCA i.p. RESULTS: The survival rate of group IV was better than that of the other groups (p < 0.05). The area under the ascitic platinum concentration-time curve and tissue concentrations of platinum in the omentum after 24 hours of treatment were higher in group IV than in groups II or III (p < 0.05). The platinum concentrations in the kidneys of group IV were lower than in group III (p < 0.05). CONCLUSION: The HAP-CBDCA combination enhances the anti-tumor effects of the drug and reduces the nephrotoxicity in rats with peritoneal carcinomatosis.

Clinicopathological and immunohistochemical analysis of malignant features in mucinous cystic tumors of the pancreas.

BACKGROUND/AIMS: To investigate the malignancy of mucinous cystic tumors (MCTs) of the pancreas, we examined clinicopathological features and immunohistochemical findings of MCT. METHODOLOGY: We analyzed the expression of p53 protein, proliferating cell nuclear antigen, alpha6-integrin subunit, alpha5beta1-integrin, and interleukin-1 receptor type I in tumor specimens from eight patients with MCT. RESULTS: The tumors were classified as mucinous cyst adenoma (n=6) or mucinous cyst adenocarcinoma (n=2). The actuarial five-year survival rate was 83.3%. All in eight MCTs had 'ovarian-type' stroma in the cyst wall. The alpha6-integrin subunit and p53 protein were expressed in adenocarcinoma tissues of MCTs, and in two adenomas the alpha6-integrin subunit and p53 protein were also co-expressed. CONCLUSIONS: Our present results indicate that coexpression of the alpha6-integrin subunit and p53 protein should be appreciated as an indicator of malignancy in MCTs.

Surgical treatment for relief of severe pain with chronic pancreatitis that is resistant to conservative treatment.

BACKGROUND/AIMS: To evaluate the surgical treatment, we investigated that performed for chronic pancreatitis patients suffering from severe pain resistant to conservative treatments. METHODOLOGY: Nineteen chronic pancreatitis patients with severe pain resistant for a long time to previous conservative medical and/or interventional treatments underwent surgery retrospectively. We evaluated a difference of postoperative improvement of symptoms in patients with surgical treatment including nerve plexus resection. RESULTS: The mean follow-up interval after surgery was 59.7 months (range, 3.0-187.3 months). Of 19 patients, 14 (73.7%) underwent nerve plexus resection. Relief of symptoms was observed in 16 of 19 patients (84.2%). Fourteen of the 15 patients (93.3%) in the nerve plexus resection group were relieved of symptoms after surgery, compared to only two of four (50.0%) patients in the nerve plexus non-resection group. CONCLUSIONS: Surgical treatments with nerve plexus resection appropriately matched with individual patients are very safe and contribute to the improvement of the quality of life for chronic pancreatitis patients resistant to conservative treatments.

Clinicopathologic study of intraductal papillary-mucinous tumors and mucinous cystic tumors of the pancreas.

BACKGROUND/AIMS: We analyzed clinicopathologic and imaging findings of intraductal papillary-mucinous tumors (IPMTs) and mucinous cystic tumors (MCTs) of the pancreas to evaluate the difference between IPMTs and MCTs, and to identify the signs indicative of malignancy in IPMTs. METHODOLOGY: Clinicopathological features of 20 patients with IPMT and six patients with MCT of the pancreas were studied. RESULTS: The patients with IPMT comprised 16 males and four females with a mean age of 62.9 years. Eighty percent of IPMTs were located in the pancreatic head, and the mean tumor size was 38.6mm. Recurrence was observed in one patient, who died of IPM adenocarcinoma. In contrast, all patients with MCT were females, with a mean age of 53.0 years. None of the MCTs arose in the pancreatic head, and the mean tumor size was 42.7mm. One patient died of MC adenocarcinoma, but all of the others survived without recurrence. The difference in gender, location of the tumor, and connection to the pancreatic duct reached statistical significance between IPMTs and MCTs. A significant connection to the pancreatic duct and high level of serum carbohydrate antigen 19-9 (CA19-9) was observed in the adenocarcinoma and moderate dysplasia groups of IPMT. CONCLUSIONS: The main duct type and an elevation of serum CA19-9 level suggested malignancy in IPMTs.

[Bacteria isolated from surgical infections and its susceptibilities to antimicrobial agents--special references to bacteria isolated between April 2003 and March 2004].

Tendency of isolated bacteria from infections in general surgery during the period from April 2004 to March 2005 were investigated in a multicenter study in Japan, and the following results were obtained. In this series, 645 strains including 17 strains of Candida spp. were isolated from 226 (79.0%) of 286 patients with surgical infections. Three hundred and seventeen strains were isolated from primary infections, and 345 strains were isolated from postoperative infections. From primary infections, anaerobic Gram-positive bacteria and anaerobic Gram-negative bacteria were predominant, while aerobic Gram-positive bacteria were predominant from postoperative infections. The isolation rate of aerobic Gram-positive bacteria, such as Enterococcus spp. and Staphylococcus aureus were higher from both types of infections. Among anaerobic Gram-positive bacteria, the isolation rate of Peptostreptococcus spp. was the highest from both types of infections. Among aerobic Gram-negative bacteria, Escherichia coli was the most predominantly isolated from primary infections, followed by Pseudomonas aeruginosa, Klebsiella pneumoniae and Citrobacter freundii in this order, and from postoperative infections, P. aeruginosa was the most predominantly isolated, followed by E. coli, E. cloacae, and K. pneumoniae. Among anaerobic Gram-negative bacteria, the isolation rate of Bacteroides fragilis group was the highest from both primary infections followed by Bilophila wadsworthia. While the isolation rate of B. fragilis group was also the highest from postoperative infections, the following bacteria were Bacteroides thetaiotaomicron and B. wadsworthia in this order. In this series, we noticed no vancomycin-resistant Gram-positive cocci, but a few strains of moderately arbekacin-resistant MRSA. Carbapenem-resistant P. aeruginosa but not multidrug-resistant was seen in 13.3 per cents. Also cefazolin-resistant E. coli probably producing extended spectrum beta-lactamase was seen in 7.0 per cents. We should be carefully followed up the facts that an increasing isolation rates of B. fragilis group and B. wadsworthia which were resistant to both penicillins and cephems.

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

BACKGROUND: Interaction with integrin and focal adhesion kinase (FAK) regulates the cancer cell adhesion and invasion into extracellular matrix (ECM). In addition, phosphorylation of FAK correlates with the increase of cell motility and invasion. Adhesion and spreading of cancer cells on a variety of ECM proteins, including collagen type IV (Coll IV), leads to an increase in tyrosine phosphorylation and activation of FAK. In this study, we investigated the mechanism of activation of FAK and its downstream extracellular signal-regulated kinase (ERK)-1/2 signaling following stimulation by interleukin (IL)-1alpha and adhesion to ECM with subsequent enhancement of pancreatic cancer cell adhesion and invasion. RESULTS: In immunoblotting analysis, all three pancreatic cancer cell lines (AsPC-1, BxPC-3, and Capan-2) expressed the protein of FAK and beta1 integrin. Enhancement of FAK protein association with beta1 integrin when cells were plated on Coll IV was more increased by stimulation with IL-1alpha. Preincubation with anti-beta1 integrin antibody and FAK siRNA transfection inhibited the association of FAK with beta1 integrin of pancreatic cancer cells. FAK phosphorylation was observed by adhesion to Coll IV, furthermore, stronger FAK phosphorylation was observed by stimulation with IL-1alpha of pancreatic cancer cells adhered to Coll IV in time-dependent manner. Genistein, a tyrosine kinase inhibitor, markedly inhibited the FAK phosphorylation. IL-1alpha stimulation and Coll IV adhesion enhanced the activation of Ras, as evidenced by the increased Ras-GTP levels in pancreatic cancer cells. Activation of Ras correlated with the phosphorylation of ERK. While not statistical affecting the apoptosis of pancreatic cancer cells, IL-1alpha-induced adhesion and invasion on Coll IV were inhibited with FAK gene silencing by siRNA, beta1 integrin blocking, and inhibition of FAK phosphorylation. PD98059, a MEK inhibitor, also inhibited IL-1alpha-induced enhancement of adhesion and invasion in pancreatic cancer cells. CONCLUSION: Our results demonstrated that activation of FAK is involved with the aggressive capability in pancreatic cancer through Ras/ERK signaling pathway. Based on our results, we suggest that the modification of IL-1, FAK, and integrins functions might be a novel therapeutic approach to aggressive spread of pancreatic cancer.

Kinetics of marked development of lung metastasis of rat prostatic carcinomas transplanted in syngeneic rats.

In order to investigate how and when metastases develop under experimental conditions, kinetics of the size and the number of lung metastasis lesions in F344 rats were examined after syngeneic transplantation of rat prostate carcinomas induced by 3,2'-dimethyl-4-aminobiphenyl (DMAB). Cell proliferation of the subcutaneous tumor and lung metastatic lesions was evaluated along with the expression of VEGF-A splicing variants and endostatin, serum VEGF levels and vascular density in the tumor. Several pieces of tumor tissue were introduced subcutaneously into two different sites on the dorsal side of F344 rats through a 14G needle. Average body weight of recipient rats markedly decreased despite only a gradual increase in tumor volume. The absolute total number of metastatic lesions in rats (n=5) were 2, 10, 19 and 194 at weeks 7.5, 9, 11 and 13, respectively, and a notable increase was observed at week 13. Similarly, the mitotic index of lung metastatic lesions increased remarkably at week 9 while the mitotic index and apoptotic index of transplanted tumors did not change throughout the experimental period. Expression of VEGF-A121, A164, A188 and endostatin, serum VEGF levels and vascular density did not correlate with the spread of lung lesions. In conclusion, both the number and the size of metastatic lesions increased at the same time after a notable increase in cell proliferation. Factors other than VEGF or endostatin may be involved in the mechanism of explosive lung metastasis spread.