Eishi Nagai

Radiation to stromal fibroblasts increases invasiveness of pancreatic cancer cells through tumor-stromal interactions.

Radiotherapy represents a major treatment option for patients with pancreatic cancer, but recent evidence suggests that radiation can promote invasion and metastasis of cancer cells. Interactions between cancer cells and surrounding stromal cells may play an important role in aggressive tumor progression. In the present study, we investigated the invasive phenotype of pancreatic cancer cells in response to coculture with irradiated fibroblasts. Using in vitro invasion assay, we demonstrated that coculture with nonirradiated fibroblasts significantly increased the invasive ability of pancreatic cancer cells and, surprisingly, the increased invasiveness was further accelerated when they were cocultured with irradiated fibroblasts. The hepatocyte growth factor (HGF) secretion from fibroblasts remained unchanged after irradiation, whereas exposure of pancreatic cancer cells to supernatant from irradiated fibroblasts resulted in increased phosphorylation of c-Met (HGF receptor) and mitogen-activated protein kinase activity, possibly or partially via increased expression of c-Met. We also demonstrated that scattering of pancreatic cancer cells was accelerated by the supernatant from irradiated fibroblasts. The enhanced invasiveness of pancreatic cancer cells induced by coculture with irradiated fibroblasts was completely blocked by NK4, a specific antagonist of HGF. These data suggest that invasive potential of certain pancreatic cancer cells is enhanced by soluble mediator(s) released from irradiated fibroblasts possibly through up-regulation of c-Met expression/phosphorylation and mitogen-activated protein kinase activity in pancreatic cancer cells. Our present findings further support the potential use of NK4 during radiotherapy for patients with pancreatic cancer.

MicroRNA-21 modulates biological functions of pancreatic cancer cells including their proliferation, invasion, and chemoresistance.

Due to the poor prognosis of pancreatic cancer, novel diagnostic modalities for early diagnosis and new therapeutic strategy are urgently needed. Recently, microRNA-21 (miR-21) was reported to be strongly overexpressed in pancreatic cancer as well as in other solid cancers. We investigated the functional roles of miR-21, which have not been fully elucidated in pancreatic cancer. miR-21 expression was assessed in pancreatic cancer cell lines (14 cancer cell lines, primary cultures of normal pancreatic epithelial cells and fibroblasts, and a human normal pancreatic ductal epithelial cell line) and pancreatic tissue samples (25 cancer tissues and 25 normal tissues) by quantitative real-time reverse transcription-PCR amplification. Moreover, we investigated the proliferation, invasion, and chemoresistance of pancreatic cancer cells transfected with miR-21 precursor or inhibitor. miR-21 was markedly overexpressed in pancreatic cancer cells compared with nonmalignant cells, and miR-21 in cancer tissues was much higher than in nonmalignant tissues. The cancer cells transfected with the miR-21 precursor showed significantly increased proliferation, Matrigel invasion, and chemoresistance for gemcitabine compared with the control cells. In contrast, inhibition of miR-21 decreased proliferation, Matrigel invasion, and chemoresistance for gemcitabine. Moreover, miR-21 positively correlated with the mRNA expression of invasion-related genes, matrix metalloproteinase-2 and -9, and vascular endothelial growth factor. These data suggest that miR-21 expression is increased in pancreatic cancer cells and that miR-21 contributes to the cell proliferation, invasion, and chemoresistance of pancreatic cancer.[Mol Cancer Ther 2009;8(5):1067–74]

Hepatoid adenocarcinoma of the stomach. A clinicopathologic and immunohistochemical analysis

Background. The clinicopathologic and immunohistochemical features of the primary gastric hepatoid adenocarcinomas still remain unclear.

Surgical treatment of patients with T2 gallbladder carcinoma invading the subserosal layer.

BACKGROUND Because T2 carcinoma of the gallbladder that invades perimuscular connective tissue without extension beyond serosa or into the liver has a hope for longterm survival, we attempted to clarify significant prognostic factors with respect to tumor- and surgery-related variables. STUDY DESIGN Of 65 patients with gallbladder carcinoma who had undergone surgical resection from 1983 to 1999, 28 had T2 carcinoma histologically proved. The significance of variables for survival was examined by the Kaplan-Meier method and log-rank test followed by multivariate analyses using Coxs proportional hazard model. RESULTS There were 17 patients with stage II carcinoma (T2 N0 M0), 6 with stage III (T2 N1 M0), and 5 with stage IVB. Lymph node metastasis was present in 11 patients (39%) and it reached to the peripancreatic head region (N2) in 5 of them. Lymphatic, venous, and perineural invasions were found in 68%, 57%, and 43%, respectively. With respect to tumor factors, the absence of perineural invasion (Odds ratio [OR] 16.77, 95% confidence interval [CI] 2.17-129.94, p = 0.0069), absence of lymph node metastasis (OR 15.00, 95% CI 2.08-108.33, p = 0.0073), and stage II (II versus III and IVB, OR 15.00, 95% CI 2.08-108.33, p = 0.0073) were significant factors related to good postoperative survival in the multivariate analysis. Surgical procedure (radical resection versus cholecystectomy, OR 4.31, 95% CI 1.34-13.82, p = 0.0142) and surgical margin (OR 7.41, 95% CI 2.19-25.13, p = 0.0013) were significant factors in the univariate analysis. Cancer-free surgical margins provided a significantly better survival (5-year survival rate, 62%); none with cancer-positive surgical margins survived for more than 27 months. In the multivariate analysis, surgical procedure was significant (OR 25.49, 95% CI 1.62-400.72, p = 0.021). Radical surgery, including extended cholecystectomy (resection of the gallbladder together with the gallbladder bed of the liver) and anatomic resection of liver segment 5 and of the lower part of segment 4, gave a significantly better 5-year survival rate than cholecystectomy (59% versus 17%). The 5-year survival rate after radical resection in patients with stage II was 75%; that in patients with stage III and IVB was 33%. CONCLUSIONS Results suggest that radical surgery is the treatment of choice for patients with T2 carcinoma of the gallbladder. The presence of lymph node metastasis, perineural invasion, or both suggests the necessity of additional treatment after radical surgery.

The Role of S100A6 in Pancreatic Cancer Development and Its Clinical Implication as a Diagnostic Marker and Therapeutic Target

Recent microarray analyses showed that the S100 family contains members that are candidate diagnostic markers or therapeutic targets. In the present study, to evaluate the involvement of S100A6 in pancreatic cancer and its clinical usefulness for diagnosis, we examined S100A6 mRNA expression in pancreatic tissues and pancreatic juice from patients with different pancreatic diseases. To investigate the role of S100A6 in carcinogenesis of pancreatic cancer and the potential of S100A6 as a diagnostic marker for early detection of pancreatic cancer, we did immunohistochemistry and microdissection-based mRNA analysis of pancreatic normal ducts, pancreatic intraepithelial neoplasias, and invasive ductal carcinomas. We also used in vitro experiments and microarray analysis with RNA interference to evaluate the functional role of S100A6 and its potential as a therapeutic target for pancreatic cancer. S100A6 mRNA levels were significantly higher in carcinoma specimens than in nonneoplastic tissues. In pancreatic juice, there was a significant difference in S100A6 expression between patients with carcinoma and those with nonneoplastic disease. Receiver operating characteristic curves revealed that S100A6 might be a useful marker for diagnosis of pancreatic cancer. Immunohistochemistry and microdissection-based analysis showed differential expression of S100A6 among normal ducts, pancreatic intraepithelial neoplasias, and invasive ductal carcinomas. In vitro data showed that inhibition of S100A6 decreased proliferation and invasiveness of cancer cells, and these findings were supported by microarray data. Our present results suggest that quantitation of S100A6 mRNA is a promising tool for diagnosis of pancreatic cancer, and that S100A6 may be a promising therapeutic target for pancreatic cancer.

Laparoscopically assisted distal gastrectomy with standard radical lymph node dissection for gastric cancer

BackgroundLaparoscopically assisted distal gastrectomy (LADG) with limited lymph node dissection (D1+alpha) has been used to treat a subset of patients with early gastric cancer. Technical advances have expanded indications for LADG to more advanced gastric cancers. However, little data are available on the feasibility or advantages of LADG with standard radical D2 lymph node dissection for patients with gastric cancer.MethodsThis study reviewed the clinical features of 37 patients who underwent LADG with D2 lymph node dissection for preoperatively diagnosed gastric carcinoma, then compared the results with the features of 31 patients who underwent conventional open distal gastrectomy (ODG) with D2 lymph node dissection.ResultsThe laparoscopic procedure was not converted to laparotomy in any patient. There was no operative mortality and no serious morbidity among the patients who underwent LADG with D2 lymph node dissection. As compared with the ODG group, the LADG group had less operative blood loss (p < 0.001), earlier recovery of bowel activity (p = 0.012), and a shorter duration of fever after surgery (p = 0.015), despite the longer operation time (p = 0.007).ConclusionsAccording to this study, LADG with D2 lymph node dissection is feasible and provides several advantages similar to those of limited lymph node dissection (D1+alpha). Depending on surgeons’ technical proficiency, LADG can be used with standard radical lymph node dissection for patients with gastric cancers.

Laparoscopic gastric surgery in a Japanese institution: analysis of the initial 100 procedures

BACKGROUND Although endoscopic surgical procedures are popular in various fields, reports on its use in gastric surgical procedures are limited. This study was designed to review our initial experience with laparoscopic gastric surgical techniques to evaluate indications and surgical results. STUDY DESIGN We undertook a retrospective analysis of 100 patients (66 men and 34 women, mean age 63 years) who underwent laparoscopic gastric surgical procedures between 1995 and 2001. Procedures performed were distal gastrectomy (n = 76), wedge resection (n = 20), and intragastric surgical procedures (n = 4). Patients were divided into two groups according to the date of the procedure, from the earliest to the most recent. RESULTS There were 85 patients with gastric cancers, 14 submucosal tumors, and 1 duodenal ulcer. In 8 cases conversion was made to an open surgical procedure. Operation times required for distal gastrectomy, wedge resection, and intragastric surgical procedures were 330 +/- 69, 144 +/- 34, and 298 +/- 106 min, and blood loss was 354 +/- 251, 56 +/- 94, and 33 +/- 58 g, respectively. Complications included transient anastomotic stenosis (n = 5), leakage (n = 4), and bleeding (n = 1) after distal gastrectomy, and bleeding (n = 1) after intragastric surgical procedures. There were no complications after wedge resection. Comparing the first and second halves of the series, the percentage of distal gastrectomy significantly increased from 66% to 86% (p = 0.02) and the number of dissected lymph nodes at this procedure increased from 20 +/- 13 to 33 +/- 17 (p < 0.01). CONCLUSIONS Laparoscopic gastric surgical procedures are safe and feasible for early gastric cancers and submucosal tumors. Technical advances in lymph node dissection have made distal gastrectomy a leading and increasingly popular laparoscopic procedure for early gastric cancer.

Laparoscopy-Assisted Distal Gastrectomy for Early Gastric Cancer: Is It Beneficial for Patients of Heavier Weight?

Objective: In this retrospective review, we evaluated the advantages and disadvantages of LADG for patients of heavier weight with early gastric cancer. Summary Background Data: LADG has been used to treat early gastric cancer. We and others have reported less operative blood loss, less pain, early recovery of bowel activity, early restart of oral intake, and a shorter hospital stay with LADG compared with a conventional open method. There is, however, little information on the advantages of LADG for obese patients with early gastric cancer. Methods: Between January 1996 and March 2002, 76 patients with preoperatively diagnosed early gastric carcinoma underwent LADG in our department. We classified these patients into 2 groups on the basis of body mass index (BMI). Nineteen patients had a high-BMI (≥ 24.2 kg/m2), and 57 patients had a normal-BMI (<24.2 kg/m2). We collected data by retrospectively reviewing the medical charts. Results: Extension of the minilaparotomic incision or conversion to laparotomy was needed in 6 (32%) of the 19 patients in the high-BMI group, whereas only 3 (5%) of 57 patients in the normal-BMI group required either. In the high-BMI group, Roux-en-Y anastomosis rather than Billroth I anastomosis was adopted more often than in the normal-BMI group, due to the difficulty of the reconstruction (58% versus 4%, P = 0.001). Significantly longer operative time (370 ± 61 minutes versus 317 ± 58 minutes, P = 0.015) and prolonged recovery of bowel activity (3.5 ± 1.0 days versus 2.6 ± 1.0 days, P = 0.007) were observed in the patients in the high-BMI group. Conclusions: In the current study, LADG in patients of heavier weight was accompanied by more technical difficulties, and the disadvantages of longer operative time and delayed recovery of bowel activity was observed in patients of heavier weight. Heavier weight appears to be an ominous factor in the successful completion of LADG and should be considered in the decision to use LADG. There are still benefits of a decreased incidence of serious wound and hernia complications in successful cases.

Correlation between centrosome abnormalities and chromosomal instability in human pancreatic cancer cells

Chromosomal instability, characterized by abnormal numbers or structures of chromosomes, is a common feature of human cancers, but the mechanisms behind these changes are still unclear. Since centrosomes play a pivotal role in balanced chromosomal segregation during mitosis, we attempted to investigate the association between centrosome abnormalities and chromosomal instability in a large number of human pancreatic cancer cell lines. Immunofluorescence microscopy revealed centrosomes that were highly atypical with respect to their size, shape, and number in most cell lines. These abnormal centrosomes contributed to the assembly of multipolar spindles, resulting in defective mitosis and chromosome mis-segregation. Interestingly, a high frequency of centrosome defects inversely correlated with the growth rate of cells in culture. Fluorescence in situ hybridization revealed a dramatic variation of chromosome numbers in cell lines with the defective centrosome phenotype. Furthermore, a significant positive correlation existed between the level of centrosome defects and the level of chromosomal imbalances. These results indicate that centrosome abnormalities can lead to spindle disorganization and chromosome segregation errors, which may drive the accumulation of chromosomal alterations. Thus, defects in centrosome function may be an underlying cause of genetic instability in human pancreatic cancers.

MicroRNA-10b is overexpressed in pancreatic cancer, promotes its invasiveness, and correlates with a poor prognosis

BACKGROUND MicroRNAs (miRNAs) have been gaining attention as new, key molecules that contribute to carcinogenesis. In pancreatic cancer, previous profiling analyses of miRNA expression have shown that several miRNAs are differently expressed in normal and cancerous tissues. Several pancreatic cancer-specific miRNAs differed, however, in each analysis. METHODS We investigated the miRNA expression profiles of the pancreatic cancer cell lines CAPAN-1 and CFPAC1 and an immortalized human normal pancreatic ductal epithelial cell line (HPDE) using a high-throughput, TaqMan, qRT-PCR array analysis. We also analyzed the expression levels of this miRNA in microdissected (n = 15) and formalin-fixed, paraffin-embedded (FFPE) (n = 115) samples from pancreatic cancers by quantitative RT-PCR. Finally, we investigated the effects of this miRNA on the invasiveness of pancreatic cancer cells. RESULTS Based on the microarray analysis, miR-372, miR-146a, miR-204, miR-10a, and miR-10b showed particularly large differences (>10-fold changes) between both pancreatic cell lines and HPDE cells. Thirteen of the 15 pancreatic cancer cell lines showed 2.1- to 36.4-fold (median, 15.3-fold) greater levels of miR-10b than HPDE cells. Microdissection analysis revealed that miR-10b exhibited greater expression levels in pancreatic cancer cells (n = 5) than in normal pancreatic ductal cells (n = 10) (P < .020). Analysis of FFPE samples showed that high miR-10b expression was associated with a lesser overall survival (P = .014). Furthermore, miR-10b correlated with the invasiveness of pancreatic cancer cells (P < .01). CONCLUSION miR-10b is overexpressed in pancreatic cancer and may be involved in the invasiveness in pancreatic cancer cells, thereby leading to a poor prognosis.