Survival outcomes of 220 consecutive patients with three-staged thoracoscopic esophagectomy.

Patients with thoracic esophageal cancer are often treated by minimally invasive esophagectomy. However, the long-term survival benefits of minimally invasive esophagectomy remain unclear. Two approaches are available for thoracoscopic surgery: one with the patient in the left lateral decubitus position (LLDP), and the other with the patient in the prone position (PP). We investigated the survival benefit of thoracoscopic esophagectomy according to the tumor stage and patient position during the thoracoscopic procedure. We reviewed the records of 220 consecutive patients with esophageal cancer treated from 1998 to 2012. In total, 146 and 74 patients were treated with thoracoscopic esophagectomy in the LLDP and PP, respectively. No patients were initially proposed to be candidates for esophagectomy by thoracotomy during the study period. Data collection was performed with a focus on survival and recurrent disease. Among all the 220 patients, the overall 5-year survival rates were 83.7%, 74.1%, 45.5%, 78.6%, 44.2%, 29.4% and 24.3% in the patients with pStage IA, IB, IIA, IIB, IIIA, IIIB and IIIC disease, respectively. Despite the greater number of dissected mediastinal lymph nodes in the PP procedure, there were no significant differences in the survival curves between the LLDP and PP procedures. The long-term results of thoracoscopic esophagectomy are comparable and acceptable. The PP procedure was not confirmed to offer a superior survival benefit to the LLDP procedure in this retrospective study.

Gemcitabine synergistically enhances the effect of adenovirus gene therapy through activation of the CMV promoter in pancreatic cancer cells.

Adenovirus-mediated gene therapy shows remarkable promise as a new strategy for advanced pancreatic cancer, but satisfactory clinical results have not yet been obtained. To improve this gene therapy, we investigated the effects of gemcitabine (GEM) on transgene expression by adenoviral vectors and their biological effects. We used Ad-lacZ and adenoviral vector-expressing NK4 (Ad-NK4) as representative adenoviral vectors. These vectors express beta-galactosidase (beta-gal) and NK4 (which inhibits the invasion of cancer cells), respectively, under the control of the CMV promoter. Cells were infected with the individual adenoviruses and then treated with GEM. GEM increased beta-gal mRNA expression and beta-gal activity, and increased NK4 expression in both culture media and within infected cells, in dose-dependent manners. The increased expression of NK4 delivered by Ad-NK4 had biological effects by inhibiting the invasion of cancer cells. GEM also enhanced NK4 expression in SUIT-2 cells transfected with an NK4-expressing plasmid, suggesting that GEM enhanced CMV promoter activity. In in vivo experiments, NK4 expression within subcutaneously implanted tumors was increased in GEM-treated mice compared with control mice. These results suggest that adenovirus-mediated gene therapy with GEM may be a promising approach for treating pancreatic cancer, and that this combination therapy may decrease the risks of side effects.

Over-expression of S100A2 in pancreatic cancer correlates with progression and poor prognosis.

Controversy exists regarding the clinical significance of S100A2 in the progression of tumours. In pancreatic cancer, little is known about the role of S100A2. The aim of this study was to clarify the clinical significance of S100A2 expression in pancreatic carcinogenesis. We microdissected invasive ductal carcinoma (IDC) cells from 22 lesions, pancreatic intraepithelial neoplasia (PanIN) cells from five lesions, intraductal papillary mucinous neoplasm (IPMN) cells from 38 lesions, pancreatitis-affected epithelial (PAE) cells from 16 lesions, and normal ductal cells from 18 normal pancreatic tissues. S100A2 expression in 14 pancreatic cancer cell lines, microdissected cells and formalin-fixed paraffin-embedded (FFPE) samples was examined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Microdissection analyses revealed that IDC cells expressed higher levels of S100A2 than did IPMN, PAE or normal cells (all comparisons, p < 0.007). Cell lines from metastatic sites expressed higher levels of S100A2 than those from primary sites. PanIN cells expressed higher levels of S100A2 than normal cells (p = 0.018). IDC cells associated with poorly differentiated adenocarcinoma expressed higher levels of S100A2 than did IDC cells without poorly differentiated adenocarcinoma (p = 0.006). Analyses of FFPE samples revealed that levels of S100A2 were higher in samples from patients who survived < 1000 days after surgery than in those from patients who survived > 1000 days (p = 0.043). Immunohistochemical analysis was consistent with qRT-PCR. S100A2 may be a marker of tumour progression or prognosis in pancreatic carcinogenesis and pancreatic cancer.

Sonic hedgehog is an early developmental marker of intraductal papillary mucinous neoplasms: clinical implications of mRNA levels in pancreatic juice.

Intraductal papillary mucinous neoplasms (IPMNs) are common cystic tumours of the pancreas. Sonic hedgehog (SHH) is involved in gastric epithelial differentiation and pancreatic carcinogenesis. However, a comprehensive analysis of SHH expression in IPMN has not yet been performed. In the present study, one-step quantitative real-time reverse transcription-polymerase chain reaction with gene-specific priming was used to examine mRNA levels in various types of clinical samples. SHH expression in IPMN was measured and the possible association of gastric epithelial differentiation with development of IPMN was evaluated. In bulk tissue analyses (IPMNs, 11 pancreatic cancer, and 20 normal pancreatic tissues), IPMN expressed significantly higher levels of SHH than did normal pancreas (IPMN versus normal pancreas, p = 0.0025; pancreatic cancer versus normal pancreas, p = 0.0132), but SHH expression did not differ between IPMN and pancreatic cancer (p = 0.3409). In microdissection analyses (infiltrating ductal carcinoma cells from 20 sections, IPMN cells from 20 sections, pancreatitis-affected epithelial cells from 11 sections, and normal epithelial cells from 12 sections), IPMN cells expressed significantly higher levels of SHH than did cancer cells, normal cells, or pancreatitis-affected ductal cells (all comparisons, p < 0.008). Pancreatic juice analyses (20 samples from pancreatic cancers, 31 samples from IPMNs, and 27 samples from chronic pancreatitis) revealed that SHH expression differed significantly between IPMN juice and pancreatitis juice (p < 0.0001), and between cancer juice and pancreatitis juice (p = 0.0125). Receiver operating characteristic curve analyses revealed that SHH measurement in pancreatic juice was useful for discriminating IPMN from chronic pancreatitis (area under the curve = 0.915; 95% confidence interval: 0.796-0.976). The data suggest that overexpression of SHH is an early event in the development of IPMN and that SHH measurement in pancreatic juice may provide some advantages for the treatment or follow-up of a subset of patients with IPMN or chronic pancreatitis.

Optimal antidiarrhea treatment for antitumor agent irinotecan hydrochloride (CPT-11)-induced delayed diarrhea.

PURPOSE: An antitumor camptothecin derivative CPT-11 has proven a broad spectrum of solid tumor malignancy, but its severe diarrhea has often limited its more widespread use. We have demonstrated from a rat model that intestinal beta-glucuronidase may play a key role in the development of CPT-11-induced delayed diarrhea by the deconjugation of the luminal SN-38 glucuronide, and the elimination of the intestinal microflora by antibiotics or dosing of TJ-14, a Kampo medicine that contains beta-glucuronidase inhibitor baicalin, exerted a protective effect. In the present study, we assessed the efficacy of several potential treatments in our rat model to clarify which is the most promising treatment for CPT-11-induced delayed diarrhea. METHODS AND RESULTS: Oral dosing (twice daily from days -1 to 4) of streptomycin 20 mg/kg and penicillin 10 mg/kg (Str/Pen), neomycin 20 mg/kg and bacitracin 10 mg/kg (Neo/Bac), both of which inhibited almost completely the fecal beta-glucuronidase activity, or TJ-14 1,000 mg/kg improved the decrease in body weight and the delayed diarrhea symptoms induced by CPT-11 (60 mg/kg i.v. from days 1 to 4) to a similar extent. The efficacy was less but significant in activated charcoal (1,000 mg/kg p.o. twice daily from days -1 to 4). In a separate experiment using rats bearing breast cancer (Walker 256-TC), TJ-14, Neo/Bac, and charcoal at the same dose regimen improved CPT-11-induced intestinal toxicity without reducing CPT-11's antitumor activity. In contrast, oral dosing (twice a day) of cyclosporin A (50 mg/kg), a P-glycoprotein and cMOAT/MRP2 inhibitor or valproic acid (200 mg/kg), a UDP-glucuronosyltranferase inhibitor, exacerbated the intestinal toxicity without modifying CPT-11's antitumor activity. CONCLUSIONS: The result clearly demonstrated the ability of Neo/Bac, Str/Pen, and TJ-14, less but significant ability of activated charcoal, to ameliorate CPT-11-induced delayed-onset diarrhea, suggesting the treatments decreasing the exposure of the intestines to the luminal SN-38 are valuable for improvement of CPT-11-induced intestinal toxicity. In contrast, the treatments affecting the biliary excretion of CPT-11 and its metabolites might have undesirable results.

Peritumoral injection of adenovirus vector expressing NK4 combined with gemcitabine treatment suppresses growth and metastasis of human pancreatic cancer cells implanted orthotopically in nude mice and prolongs survival.

NK4 or adenovirus vector expressing NK4 (Ad-NK4) can act bifunctionally as a hepatocyte growth factor antagonist and angiogenesis inhibitor and has potential value in cancer therapy. The aim of this study was to evaluate the therapeutic efficacy of Ad-NK4 in combination with gemcitabine (GEM) against pancreatic cancer. In vitro study showed a strong antiproliferative effect of GEM and a potent anti-invasive effect of Ad-NK4 against pancreatic cancer cells. In in vivo experiments, SUIT-2 human pancreatic cancer cells were implanted into the pancreas of nude mice. Mice were treated with Ad-NK4 by injection into the peritumoral region of the pancreas on day 5 after implantation followed by weekly i.p. injections of GEM. On day 28 after implantation, pancreatic tumor volume was significantly smaller than that in mice treated with Ad-LacZ, Ad-NK4 alone, or GEM alone. Furthermore, combination therapy completely suppressed peritoneal dissemination and liver metastases, leading to significantly increased survival. Histologic and immunohistochemical assays of primary tumors indicated that combination therapy prohibited both cell proliferation and angiogenesis, resulting in high levels of apoptosis. These results suggest that peritumoral injection of Ad-NK4 plus GEM is a potent combination therapy for pancreatic cancer.

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

BACKGROUND: Laparoscopically 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. METHODS: This 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. RESULTS: The 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). CONCLUSIONS: According 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 wedge resection of gastric submucosal tumors.

BACKGROUND/AIMS: The purpose of this study was to evaluate the clinical utility of laparoscopic surgery for gastric submucosal tumor. METHODS: The records of 11 patients who underwent laparoscopic wedge resection (LR group) for gastric submucosal tumors were reviewed and compared with those of 8 patients who underwent open surgery (OS group). RESULTS: Mean operation time was 145 +/- 43 min in the LR group and 127 +/- 33 min in the OS group (p = 0.301). Mean blood loss was 97 +/- 107 and 107 +/- 47 g, respectively (p = 0.387). Patients in the LR group began walking 1.4 +/- 0.7 days after surgery, which was significantly earlier than those in the OS group (2.7 +/- 1.3 days, p = 0.021). The first flatus (1.5 +/- 0.5 vs. 3.1 +/- 0.6 days, respectively, p = 0.0004) and resumption of oral food intake (3.0 +/- 1.7 vs. 4.3 +/- 0.9 days, respectively, p = 0.020) were also earlier in the LR group. White blood cell count on the first postoperative day was lower (7,000 +/- 2,100 vs. 11,900 +/- 3,580/mm(3), respectively, p = 0.004) in the LR group than in the OS group, and the duration of fever (>38.0 degrees C; 0.1 +/- 0.3 vs. 0.9 +/- 0.8 days, respectively, p = 0.014) and the period of postoperative hospitalization (13.2 +/- 3.7 vs. 20.8 +/- 6.1 days, respectively, p = 0.014) were significantly shorter in the LR group than in the OS group. No complications occurred in either group. CONCLUSION: Laparoscopic surgery was superior to open surgery in terms of postoperative recovery time with comparable operation time and blood loss. Laparoscopic wedge resection is a promising surgical alternative for the treatment of gastric submucosal tumors.

Pancreatoduodenectomy for pancreatic head carcinoma with or without pylorus preservation.

BACKGROUND/AIMS: With the concept of less invasive surgery, PpPD (pylorus-preserving pancreatoduodenectomy) has taken the place of conventional Whipple pancreatoduodenectomy (Whipple) as a standard operation for pancreatic head carcinoma. The aim of this paper is to compare early and late postoperative results of PpPD and Whipple for pancreatic head carcinoma. METHODOLOGY: Postoperative clinical follow-up data and outcome of 50 Japanese patients with pancreatic head carcinoma who underwent pancreatoduodenectomy with or without pylorus preservation were reviewed to scrutinize the demerits and merits of the pylorus preservation. RESULTS: Preoperative and postoperative serum chemistry was not different between the two groups. Mean operation time of the Whipple group was 517 minutes, which was significantly shorter than 624 minutes of the PpPD group (P = 0.0006). Cumulative stage was not different between the two groups. Cumulative curability of the PpPD group was superior to the Whipple group; of the 27 patients with Whipple, A in 4, B in 5 and C in 18, while of the 23 patients with PpPD, A in 12, B in 2 and C in 9 (P = 0.0182). Gastric tube was removed on POD 6.0 in the Whipple group, while on POD 39 in the PpPD group (P < 0.0001). Oral intake was started on POD 14.0 in the Whipple group, while on POD 28.3 in the PpPD group (P = 0.0018). Discharge was on POD 57.8 in the Whipple group, while POD 86.9 in the PpPD group (P = 0.0023). At the time of discharge and postoperative 6, 12, and 18 months, body weight loss from the preoperative level was 1kg smaller in the PpPD group than in the Whipple group. 1-year and 3-year survival rates of the Whipple group was 53.8% and 15.8%, while 62.8% and 19.6% of the PpPD group, showing no significant difference. CONCLUSIONS: These data show that delayed gastric emptying is evident in the PpPD group, resulting in longer hospital stay, while long-term body weight loss is smaller in this group. The clinical outcome is similar between the two groups. PpPD can be accepted as a standard operation for pancreatic head carcinoma.

Benign pseudotumorous lesion (fibroangiomyomatous hyperplasia with elastosis) in the gallbladder.

We describe a rare case of a benign pseudotumorous lesion (fibroangiomyomatous hyperplasia with elastosis) in the gallbladder in a 44-year-old Japanese woman, and discuss the rarity of elastosis in the gallbladder. To our knowledge, this case may be the first report of a pseudotumorous lesion of the gallbladder with elastosis in Japan.

Stepwise progression of centrosome defects associated with local tumor growth and metastatic process of human pancreatic carcinoma cells transplanted orthotopically into nude mice.

Recent evidence indicates that loss of centrosome integrity may be a major cause of genetic instability underlying various human cancers. The aim of this study was to define the role of centrosome defects during the in vivo tumor progression of pancreatic carcinoma using an orthotopic implantation model. Injection of Suit-2 human pancreatic cancer cells into the pancreata of nude mice reproduced the pattern of local tumor growth and distant metastasis observed in humans. Pancreatic xenografts, peritoneal disseminations, and hepatic metastases were harvested, and tumor cells were examined for centrosomes by immunofluorescence microscopy. Centrosome abnormalities, characterized by increased numbers of centrosomes, were detected in only a small fraction of parental Suit-2 cells in culture, whereas the frequency was markedly increased in cells isolated from the pancreatic xenografts. Abnormal centrosome numbers were found at higher frequencies in metastatic foci than in pancreatic xenografts. A significant positive correlation existed between the fraction of cells with multiple centrosomes and that with multipolar mitotic spindles, suggesting a functional involvement of aberrant centrosomes in spindle disorganization and chromosome missegregation. In addition, the increased frequency of abnormal centrosomes was associated with an enhanced degree of chromosomal instability. These findings suggest a novel model of pancreatic tumor progression whereby a stepwise increase in the magnitude of centrosomal abnormalities confers an increased chance for aberrant mitotic events, thus accelerating genetic instability and causing the tumor to progress to a more advanced stage.

Effect of serum depletion on centrosome overduplication and death of human pancreatic cancer cells after exposure to radiation.

The tumor microenvironment is one of the key factors affecting the cellular response to radiation; however, the influence of serum concentration on tumor radiosensitivity remains poorly understood. We recently discovered that gamma-irradiation of tumor cells causes centrosome overduplication, which may lead to lethal nuclear fragmentation through the establishment of multipolar mitotic spindles. In the present study, we investigated the effect of serum depletion on radiation-induced cell death in relation to the centrosome dynamics in human pancreatic cancer cells. Exposure of Capan-1 cells to gamma-irradiation resulted in a time-dependent increase in cells containing multiple centrosomes in association with the appearance of mitotic cell death. Treatment of irradiated cells with serum depletion drastically accelerated centrosome overduplication and the formation of multipolar spindles, resulting in increased nuclear fragmentation and cell death. Cell cycle analysis of irradiated cultures revealed that the reduced serum level increased the population of cells arrested in the G2/M phase, which might be responsible for the abnormal centrosome accumulation. These findings suggest that serum concentration can influence radiation-induced cell killing through modulating cell cycle progression and possibly centrosome overduplication.

Quantitative analysis of hTERT mRNA expression in colorectal cancer.

OBJECTIVES: Telomerase is highly activated in a variety of malignant neoplasms including colon cancer. Among the major components of telomerase, human telomerase reverse transcriptase (hTERT) is thought to regulate telomerase activity. To assess the importance of telomerase for the diagnosis of colorectal cancer, we measured the expression of hTERT mRNA and telomerase activity in a large series of 140 colorectal cancers, 140 adjacent normal tissues, and 20 adenomas. METHODS: The expression level of hTERT was measured quantitatively by competitive reverse transcriptase-polymerase chain reaction (RT-PCR), and telomerase activity was examined by telomeric repeat amplification protocol (TRAP) assay in the same samples. RESULTS: The median expression level of hTERT mRNA in carcinomas was significantly higher than that in either adenomas or normal tissues. The median level of hTERT in adenomas was significantly higher than that in normal tissues. Telomerase activities in carcinomas were significantly higher than those in either adenomas or normal tissues. Telomerase activities in adenomas were also significantly higher than those in normal tissues. Furthermore, the relative expression levels of hTERT mRNA in adenomas and carcinomas were significantly correlated with the relative telomerase activities; the Spearman rank correlation was 0.53 (p = 0.021) and 0.18 (p = 0.031), respectively. CONCLUSIONS: Our data suggest that determination of hTERT mRNA by competitive RT-PCR is superior in quantitative accuracy and sensitivity and would support the importance of telomerase activity for the diagnosis of colorectal cancer.

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 Cox's 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.

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.

Possible role of telomerase activation in the multistep tumor progression of periampullary lesions in patients with familial adenomatous polyposis.

OBJECTIVES: The role of telomerase in periampullary tumor progression in patients with familial adenomatous polyposis (FAP) was investigated. METHODS: Relative telomerase activity was measured using a telomerease amplification protocol in periampullary biopsy specimens of normal mucosa and adenoma obtained from patients with FAP, and was compared with that of periampullary normal mucosa and cancer specimens from patients without FAP. RESULTS: None of normal mucosa from the non-FAP patients showed a telomerase ladder. Telomerase was positively detected in three of seven normal mucosa (42.9%) and in five of seven adenoma from FAP patients (62.5%). In papillary cancer from the non-FAP patients, seven of nine tissue specimens (77.8%) showed positive activity. When semiquantitatively analyzed, the relative telomerase activity increased in accordance with the progression of the diseases. CONCLUSIONS: Telomerase is activated even in normal mucosa of FAP patients, and the intensities of telomerase may reflect the malignant potential of periampullary neoplasms.

Instability of chromosome 8 as an indicator of aggressive tumor phenotype in pancreatic cancer.

BACKGROUND AND OBJECTIVES: Chromosomal instability is a common feature of pancreatic carcinoma, but its biological significance remains unclear. In this study, we investigated the association between chromosomal instability and biological aggressiveness in human pancreatic cancer cells. METHODS: Fluorescence in situ hybridization was performed to examine changes in chromosomal numbers in a total of 13 pancreatic cancer cell lines. We also assessed the potential for tumor aggressiveness within cancer cells by in vitro migration and invasion assay and by subcutaneous implantation into nude mice. RESULTS: Chromosomal instability, characterized by numerical variations in copy numbers of chromosome 8, was observed in most cell lines, and the magnitude of instability was correlated well with both motility (P < 0.001) and invasion rate (P < 0.001) of these cells. Furthermore, a significant positive correlation existed between chromosome instability and tumor growth in vivo (P < 0.01). CONCLUSIONS: These results suggest that the increased level of chromosomal instability may play a critical role in the development of aggressive tumor phenotype during pancreatic cancer progression. J. Surg. Oncol. 2001;76:181-187.

Telomerase activity of cultured human pancreatic carcinoma cell lines correlates with their potential for migration and invasion.

BACKGROUND: Despite the recent clinical finding that high telomerase activity is an unfavorable prognostic marker for various human malignant tumors, there has been no experimental evidence supporting the link between telomerase and tumor aggressiveness. In the current investigation, the authors examined the relation between telomerase activity and potential for biologic aggressiveness in human pancreatic carcinoma cells. METHODS: Telomerase activity was measured in a poorly metastatic cell line HPC-3 and its highly metastatic variant HPC-3H4, as well as in many pancreatic carcinoma cell lines. Aggressive behavior of cancer cells was assessed by in vitro migration and invasion assay. RESULTS: Compared with parental HPC-3, HPC-3H4 displayed higher telomerase activity, which was associated with a scattered phenotype and enhanced migration activity. Furthermore, the authors found that relative telomerase levels correlated well with both motility (P = 0.0041) and invasion (P = 0.0114) in 13 pancreatic carcinoma cell lines. There was, however, no significant association between telomerase activity and cell proliferation. When telomerase activity of KP-1N cells was inhibited by transfection with antisense oligonucleotides, their motility and invasion rates were significantly decreased. CONCLUSIONS: The authors concluded that the magnitude of telomerase activation may reflect the potential for aggressive behavior within cancer cells. These findings support the clinical utility of telomerase activity as a prognostic indicator. Their results also suggest a therapeutic potential for telomerase inhibitors to prevent tumor invasion and possibly metastasis.

GM-CSF gene therapy using adenoviral vector in hamster pancreatic cancer.

The aim of this study was to examine the antitumor effect of irradiated granulocyte macrophage-colony-stimulating factor (GM-CSF)-gene-transduced hamster pancreatic cancer cells and its relationship to the amount of GM-CSF produced by transduced tumor cells. Hamster pancreatic adenocarcinoma cells, HPD1NR, which spontaneously secrete 15.0+/-0.4 pg/106 cells per 24 h of GM-CSF, and HPD2NR cells, which do not secrete GM-CSF, were used. When these cells were infected with recombinant adenovirus harboring the GM-CSF gene, HPD1NR and HPD2NR secreted 624.2+/-9.9 and 157.8 +/-5.7 pg/106 cells per 24 h, respectively. Vaccination with irradiated GM-CSF-secreting HPD2NR completely protected syngeneic hamsters challenged with live parental cells. On the other hand, vaccination with irradiated HPD1NR protected 60% of hamsters from tumor development after challenge with parental cells. None of the tumor-free hamsters initially vaccinated with irradiated GM-CSF-producing HPD2NR cells developed tumor upon repeated challenge with parental cells during the entire observation period. Irradiated GM-CSF-gene-transduced hamster pancreatic cells are promising as a novel adjuvant cancer therapy after surgery for primary and metastatic pancreatic cancer. The results indicate the necessity for a therapeutic strategy for cancer based on the cytokine status of tumors.

Truncated TSG101 transcripts in human leukemia and lymphoma cell lines.

Inactivation of the TSG101 gene has been shown to induce cellular transformation of NIH3T3 fibroblasts, and aberrant TSG101 transcripts have been observed not only in various human solid tumors but also in hematopoietic malignant disorders. In the present study, we performed nested reverse transcription/polymerase chain reaction (RT-PCR) analysis to identify aberrant TSG101 transcripts in 43 human leukemia and lymphoma cell lines. We could detect only a single band of the wild-type transcript with the expected size in virtually all cell lines after the first round of PCR. As in the case with various human solid tumors, the smaller TSG101 transcripts appeared in most of these cell lines after the second round of PCR. Thus, the expression level of the variant transcripts was extremely low as compared with that of the wild-type transcript, and this finding was also confirmed by Northern blot analysis. Identification of various truncated transcripts with extensive deletions in the TSG101 coding region was confirmed by means of sequencing analysis, and expression of these transcripts did not appear to be associated with a specific type of hematopoietic malignant disorder. Southern blot analysis did not indicate any gross TSG101 gene rearrangement. The truncated transcripts were also detected in normal peripheral blood leukocytes. Our results suggest that the truncated TSG101 transcripts are definitely detectable in various human leukemia and lymphoma cell lines, but do not support the notion that the variant transcripts may have a major functional relevance in the pathogenesis of human hematopoietic malignant disorder.