Biomedical subjects

Masayuki Imamura

Publications and source records attributed to Masayuki Imamura.

At least 109 records · Page 6Linked to original sources

PubMed2002

Intramuscular metastasis from gastric cancer.

Skeletal muscle is an uncommon site of hematogenous metastasis of gastric carcinoma. We report here a rare case of gastric carcinoma with multiple intramuscular metastases. Our patient had advanced gastric carcinoma and complained of left gluteal induration with tenderness. Because magnetic resonance imaging (MRI) revealed that the gluteal tumor showed iso-signal intensity on T1-weighted images and high signal intensity on T2-weighted images, with reticulated texture around the tumor, and the patient had advanced gastric carcinoma, we speculated that the tumor was an intramuscular metastatic tumor from primary gastric carcinoma. There were also multiple intramuscular metastatic lesions in both gluteal muscles on the MRI findings that were not detected by physical examination. Therefore, the patient underwent total gastrectomy with combined resection of spleen, with subsequent chemotherapy. Three months after the operation, we excised the gluteal tumor to alleviate the gluteal pain. Histological examinations confirmed that the gluteal tumor was a metastasis from primary gastric carcinoma.

Adenocarcinoma↗

PubMed2002

A novel suicide gene therapy system for p53-mutated cells using a wild-type p53-specific promoter and Cre/loxP switch.

Approximately half of all malignant tumors have a mutation or deficiency in the p53 tumor suppressor gene. The present study was designed to develop a p53-mutated cancer cell-specific suicide gene therapy system using p53 as a transcriptional activating factor. We introduced the promoter containing the wild-type p53-specific binding sequence (p53SP) and the Cre/loxP exchange system to induce specific expression of the herpes simplex viral thymidine kinase (HSV-tk) gene in p53-mutated cells. The transfection of an enhanced green fluorescent protein (EGFP) reporter gene expression vector containing p53SP resulted in selective EGFP expression in wild-type p53-producing cells, but not in p53-mutated cells. To express HSV-tk alone in the p53-mutated cells, two plasmid vectors were prepared: one regulator plasmid vector to express Cre under the control of the p53SP promoter (p53Cre), and another tk expression vector driven by the CAG promoter containing loxP sites at both ends of the HSV-tk gene (pCALtkL). The cotransfection of p53Cre with pCALtkL preferentially reduced the expression of HSV-tk in the wild-type p53-producing cells, but not in the p53-mutated cells. This cotransfection led to selective growth inhibition in the cotransfected p53-mutated cells mediated by ganciclovir, whereas a single transfection of pCALtkL caused nonselective growth inhibition in both cell lines following ganciclovir treatment. Thus, the HSV-tk expression system containing the wild-type p53-specific promoter and the Cre/loxP switch endabled the selective growth inhibition of p53-mutated cancer cells.

DNA-Binding Proteins↗

PubMed2002

Heparin accelerates liver regeneration following portal branch ligation in normal and cirrhotic rats with increased plasma hepatocyte growth factor levels.

BACKGROUND/AIMS: Heparin is widely used as a general anticoagulant, and has been recently reported to elevate plasma hepatocyte growth factor (HGF) levels by releasing HGF sequestrated in the extracellular matrix. Therefore, we investigated the effects of heparin administration on liver regeneration following portal branch ligation (PBL) in normal and cirrhotic rats. METHODS: Dimethylnitrosamine-induced cirrhotic rats and control rats underwent portal ligation of the left lateral and median branches, followed by intraperitoneal heparin injections, every 12 h. To examine the feasibility of an extensive hepatectomy in the cirrhotic livers, cirrhotic rats with or without heparin treatment underwent resection of occluded lobes at 72 h after the PBL. RESULTS: Heparin injections significantly augmented liver regeneration after PBL in both normal and cirrhotic rats, following an increase in hepatocellular DNA synthesis at 24 h after the PBL. The plasma HGF concentrations were elevated by heparin treatment in both groups. In addition, heparin administration dramatically improved the survival rate after an extensive hepatectomy in the cirrhotic rats. CONCLUSIONS: Heparin treatment significantly accelerated liver regeneration following the PBL, with an increase in the plasma HGF levels in both normal and cirrhotic rats. Heparin administration may make an extensive hepatectomy clinically feasible even for cirrhotic livers.

Animals↗

PubMed2002

Retinoid signaling controls mouse pancreatic exocrine lineage selection through epithelial-mesenchymal interactions.

BACKGROUND & AIMS: The early embryonic pancreas gives rise to exocrine (ducts and acini) and endocrine lineages. Control of exocrine differentiation is poorly understood, but may be a critical avenue through which to manipulate pancreatic ductal carcinoma. Retinoids have been shown to change the character of pancreatic ductal cancer cells to a less malignant phenotype. We have shown that 9-cis retinoic acid (9cRA) inhibits acinar differentiation in the developing pancreas, in favor of ducts, and we wanted to determine the role of retinoids in duct versus acinar differentiation. METHODS: We used multiple culture systems for the 11-day embryonic mouse pancreas. RESULTS: Retinoic acid receptor (RAR)-selective agonists mimicked the acinar suppressive effect of 9cRA, suggesting that RAR-RXR heterodimers were critical to ductal differentiation. RARalpha was only expressed in mesenchyme, whereas RXRalpha was expressed in epithelium and mesenchyme. Retinaldehyde dehydrogenase 2, a critical enzyme in retinoid synthesis, was expressed only in pancreatic epithelium. 9cRA did not induce ductal differentiation in the absence of mesenchyme, implicating a requirement for mesenchyme in 9cRA effects. Mesenchymal laminin is necessary for duct differentiation, and retinoids are known to enhance laminin expression. In 9cRA-treated pancreas, immunohistochemistry for laminin showed a strong band of staining around ducts, and blockage of laminin signaling blocked all 9cRA effects. Western blot and RT-PCR of pancreatic mesenchyme showed laminin-beta1 protein and mRNA induction by 9cRA. CONCLUSIONS: Retinoids regulate exocrine lineage selection through epithelial-mesenchymal interactions, mediated through up-regulation of mesenchymal laminin-1.

Alitretinoin↗

PubMed2002

Surgical management of intraductal papillary mucinous tumor of the pancreas.

BACKGROUND: Intraductal papillary mucinous tumor (IPMT) is a type of pancreatic cystic neoplasm. IPMT consists of intraductal papillary mucinous adenoma (benign IPMT) and intraductal papillary mucinous carcinoma (malignant IPMT). Preoperative diagnosis of malignancy is difficult; the invasiveness and metastatic character are not well known. The purpose of the study was to evaluate the optimal diagnostic and therapeutic strategy of IPMT. METHODS: Medical charts of 38 patients with final diagnosis of IPMT in Kyoto University Hospital were retrospectively reviewed. Preoperative imaging, mode of operation, and clinical and histopathologic findings were analyzed. RESULTS: In 38 IPMTs, imaging of localization was correct in 82% by computed tomography, 90% by ultrasonography, 70% by endoscopic retrograde cholangiopancreatography, 100% by magnetic resonance cholangiopancreatography, and 100% by endoscopic ultrasonography. Evaluation of malignancy by endoscopic ultrasonography resulted in sensitivity and specificity of 81% and 78%, respectively. Pylorus-preserving pancreaticoduodenectomy was preferably performed in 20 of 38 patients with IPMT. Twenty-two patients had histologically malignant disease. Half of them had an invasive component in the adjacent stroma. One case of malignant IPMT showed lymph node metastasis, and the patient had no recurrence after pancreaticoduodenectomy with regional lymphadenectomy. No case was diagnosed as margin positive; however, 27% showed a dysplasia with atypia in the epithelial cells of the cut edge of the pancreas. One patient with negative atypia at the cut edge of the pancreas developed a recurrent tumor in the remnant pancreas. CONCLUSIONS: The preoperative diagnosis of malignancy is difficult, and 50% of malignant IPMT showed an invasive component. Thus, radical resection of the pancreas with regional lymph node dissection should be the choice of treatment. Lymph node metastasis and intraductal distant invasion should be carefully managed in the surgical treatment of these lesions.

Adult↗

PubMed2002

Indications for abdominal para-aortic lymph node dissection in patients with esophageal squamous cell carcinoma.

BACKGROUND: Abdominal para-aortic lymph node (APAL) dissection of esophageal cancer is not widely accepted. The aim of this article is to propose the indications for APAL dissection in esophageal cancer patients from the viewpoint of micrometastases. METHODS: To evaluate the value of APAL dissection in patients with esophageal cancer, the status of APAL metastases and recurrence in 230 patients with esophageal squamous cell carcinoma (1989 to 1998) was examined retrospectively. On the basis of our findings, 16 patients received a prophylactic APAL dissection from January 1999 to March 2001. Micrometastases in the dissected lymph nodes were examined using cytokeratin staining and reverse transcription-polymerase chain reaction of squamous cell carcinoma antigen messenger RNA. RESULTS: Among the 230 patients who had esophageal squamous cell carcinoma, 21 had APAL metastases (including micrometastases) or APAL recurrence. Among the 21 patients with APAL metastases and recurrence, 20 (95.2%) had metastases (including micrometastases) in perigastric lymph nodes (paracardial and lesser curvature nodes). Among 51 patients with lower thoracic esophageal carcinoma, 13 (25.5%) had APAL metastases or recurrence. On the basis of these results, prophylactic APAL dissection was performed in patients with lower thoracic esophageal cancer who were suspected of perigastric lymph node metastases during operations. APAL metastases (including micrometastases) were detected in 6 (38%) of these patients, and 2 patients with APAL micrometastases survived without recurrence. However, 7 patients had hematogenic recurrence after the operation. CONCLUSIONS: Our results suggested that the indications for APAL dissection were limited. Patients with lower thoracic esophageal cancer who are suspected to have perigastric lymph node metastasis and APAL micrometastases may be considered for APAL dissection.

Adult↗

PubMed2002

Novel targets for the 18p11.3 amplification frequently observed in esophageal squamous cell carcinomas.

Amplification of DNA in certain chromosomal regions, with consequent over-expression of specific genes within these amplicons, plays a crucial role in the development and progression of human cancer. Since our previous comparative genomic hybridization (CGH) study revealed frequent amplifications at 18p in esophageal squamous cell carcinomas (ESC) cell lines, we focused on the identification of genetic target(s) within the 18p amplicon. In four cell lines having remarkable copy-number amplification with homogeneously staining region (HSR) pattern by fluorescence in situ hybridization (FISH), the smallest common region of overlapping covered approximately 3.5 Mb at 18p11.3. We screened 29 ESC cell lines to discern amplifications and expression levels of 14 known genes and 21 uncharacterized transcripts within the amplicon. Only four known genes, YES1, TYMS, HEC and TGIF showed amplification and consequent over-expression. These genes were amplified in several of primary ESCs. Moreover, resistance to transforming growth factor beta (TGFbeta)-induced growth inhibition was enhanced in four cell lines with amplification and expression of TGIF, which encodes the repressor for TGFbeta-activated transcription, appears to be involved in the progression of ESC. Taken together, these results suggest that YES1, TYMS, HEC and TGIF are likely to be candidate targets for 18p11.3 amplification and be associated with esophageal tumorigenesis.

Carcinoma, Squamous Cell↗

PubMed2002

Suppression of N-nitrosomethylbenzylamine (NMBA)-induced esophageal tumorigenesis in F344 rats by resveratrol.

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a natural product occurring in grapes and various other plants with medicinal properties associated with reduced cardiovascular disease and reduced cancer risk. To evaluate the possibility and potential mechanism(s) of which resveratrol inhibits N-nitrosomethylbenzylamine (NMBA)-induced rat esophageal tumorigenesis, 96 F344 male rats were divided into 10 groups and resveratrol (1 and 2 mg/kg) was administered orally or intraperitoneally (i.p.). In the groups in which resveratrol was administered at 2 mg/kg (orally, for 16 weeks), 1 and 2 mg/kg (i.p., for 16 weeks) and 1 mg/kg (i.p., for 20 weeks), the number of NMBA-induced esophageal tumors per rat was significantly reduced to 78, 62, 54 and 48, respectively (P < 0.05), and the size of maximum tumors in each group with resveratrol treatment was also significantly smaller than that in NMBA alone group (P < 0.05). Although the pathological examination did not indicate significantly decreased incidence of carcinomas by administering resveratrol, the tendency of carcinogensis suppression was observed (P = 0.177). Semi-quantitative RT-PCR and ELISA analysis demonstrated that following NMBA treatment, the expression of COX-1 mRNA was strongly present in tumor tissues, while weakly present in non-tissues; the expression of COX-2 mRNA was induced in both tumor and non-tumor tissues. The production of prostaglandin E(2) (PGE(2)) increased approximately 6-fold, compared with the normal esophageal mucosa. The higher expression of COX-1, the up-regulated COX-2 expression and the increased levels of PGE(2) synthesis were all significantly decreased by administering resveratrol. Our study suggests that resveratrol suppressed NMBA-induced rat esophageal tumorigenesis by targeting COXs and PGE(2), and therefore may be a promising natural anti-carcinogenesis agent for the prevention and treatment of human esophageal cancer.

Animals↗

PubMed2002

Expression of integrin alphaVbeta3 in pancreatic carcinoma: relation to MMP-2 activation and lymph node metastasis.

INTRODUCTION: Overexpression of integrin alphaVbeta3 had been demonstrated in various tumors. Studies have suggested that elevated levels of integrin alphaVbeta3 in melanoma cells are deeply involved in the mechanism of increased melanoma invasiveness. AIMS: To examine the expression of integrin alphaVbeta3 in pancreatic carcinoma and to evaluate the correlation between integrin expression accompanied by MMP-2 activation and clinicopathologic factors. METHODOLOGY: Integrin alphaVbeta3 specific antibody LM-609 was used for immunochemical analysis, and intracellular localization was determined in human pancreatic cancer cell lines cultured on vitronectin coating. Fifty pancreatic adenocarcinomas analyzed immunohistochemically and 26 frozen samples were analyzed gelatin-zymographically. RESULTS: Two of three pancreatic cancer cell lines demonstrated integrin alphaVbeta3 immunofluorescence with a membranous pattern, and 29 of 50 pancreatic carcinomas showed positive immunostaining of tumor cells. There was no significant correlation between integrin alphaVbeta3 expression and tumor size, tumor grade, or peripancreatic invasion. However, primary tumors with lymph node metastasis featured significantly higher expression of integrin alphaVbeta3 than those without node metastasis. Tumors with high integrin alphaVbeta3 expression showed significantly higher MMP-2 activation ratios than did tumors with low expression. CONCLUSION: Expression analysis in pancreatic cancer tissue demonstrated involvement of alphaVbeta3 integrin in lymph node metastasis rather than peripancreatic invasion. MMP-2 activation is linked, at least in part, to the expression of integrin alphaVbeta3 of pancreatic cancer cells.

Aged↗

PubMed2002

Expression of cyclooxygenase-2 is associated with carcinogenesis of the lower part of thoracic esophageal squamous cell carcinoma and p53 expression.

Cyclooxygenase (COX) is a key enzyme in arachidonic acid metabolism. Two isoforms of this enzyme have been identified: constitutive COX-1 and inducible COX-2. Recently, expression of COX-2 has been found in several human carcinomas. COX-2 expression may contribute to the synthesis of prostanoids, which relate to carcinogenesis and tumor progression. We investigated the expression of COX-2 in 175 human esophageal squamous cell carcinoma tissues using immunohistochemistry and evaluated the relationship with clinicopathological findings. In addition, due to the known relevance of p53 to carcinogenesis, we evaluated the expression of COX-2 and p53. Interestingly, cancer tissues with high COX-2 expression were found significantly more often in the middle and lower esophagus than in the cervical and upper esophagus (p = 0.0014). No significant differences were observed in other clinicopathological data such as age, sex, histopathological grading, lymphatic invasion, venous invasion, TNM clinical classification and patient prognosis. p53 expression was associated with the expression of COX-2 (p = 0.0122). Our findings suggest that COX-2 may play a role in the development of squamous cell carcinoma in the lower part of the thoracic esophagus.

Adult↗

PubMed2002

Clinicopathological significance of human macrophage metalloelastase expression in esophageal squamous cell carcinoma.

OBJECTIVE: Human macrophage metalloelastase is referred to as matrix metalloproteinase (MMP-12), its function in tumors is contradictory. The current study was undertaken to investigate the role of MMP-12 in esophageal squamous cell carcinoma (SCC). PATIENTS AND METHODS: We analyzed the levels of MMP-12 mRNA expression in 67 patients with primary esophageal SCC by Northern blot analysis and the tissues were subjected to in situ hybridization analysis for MMP-12. Immunohistochemical staining was performed to detect the macrophages infiltrated in esophageal SCCs. RESULTS: MMP-12 mRNA was detected in 27 of 67 esophageal SCC samples by Northern blot analysis. In situ hybridization and immunohistochemical staining revealed that MMP-12 mRNA signals are located mainly in tumor cells. The frequency of lymph node metastasis was significantly higher in the MMP-12-positive (MMP-12(+)) subgroup than MMP-12-negative (MMP-12(-)) subgroup (p < 0.05); furthermore, invasion was significantly deeper in the MMP- 12(+) subgroup than in the MMP-12(-) subgroup (p < 0.01). MMP-12 mRNA was inversely correlated with prognosis (p < 0.05). However, Cox multivariate analysis revealed that upregulation of MMP-12 was not related to prognosis. CONCLUSIONS: MMP-12 gene expression was associated with the progression of esophageal SCC; however, it was not an independent prognostic factor.

Aged↗

PubMed2002

Ghrelin expression in islet cell tumors: augmented expression of ghrelin in a case of glucagonoma with multiple endocrine neoplasm type I.

Ghrelin is a 28-amino acid peptide that regulates GH release together with GHRH and somatostatin. The expression of ghrelin has been detected in the stomach, small intestine, hypothalamus, pituitary gland, kidney, placenta, and testis. Recently it was reported that ghrelin is present in pancreatic alpha-cells and that it stimulates insulin secretion. In this study, we examined the ghrelin expression in two cases of glucagonoma and two cases of insulinoma by Northern blot analysis and immunohistochemistry. Ghrelin expression was identified in a case of glucagonoma associated with multiple endocrine neoplasm type I both by Northern blot analysis using total RNA and by immunohistochemistry, although the plasma ghrelin level was not elevated. This is the first case of tumor in which ghrelin gene expression was detected by Northern blot analysis using total RNA.

Adenoma, Islet Cell↗

PubMed2002

High-dose calcium stimulation test in a case of insulinoma masquerading as hysteria.

It is reported that some cases with insulinoma present with neuropsychiatric symptoms and are often misdiagnosed as psychosis. Here we report a case of insulinoma masquerading as hysteria, whose final diagnosis could be made using high-dose calcium stimulation test. A 28-yr-old woman was referred presenting with substupor, mutism, mannerism, restlessness, and incoherence. Laboratory examinations revealed hypoglycemia (33 mg/dL) and detectable insulin levels (9.7 microU/mL), suggesting the diagnosis of insulinoma. However, neither imaging studies nor selective arterial calcium injection (SACI) test with a conventional dose of calcium (0.025 mEq/kg) indicated the tumor. High-dose calcium injection (0.05 mEq/kg) evoked insulin secretion when injected into superior mesenteric artery. A solitary tumor in the head of the pancreas was resected, and her plasma glucose returned to normal. Postoperatively, iv injection of secretin resulted in a normal response of insulin, which was not found preoperatively. This case suggests the usefulness of the SACI test with high-dose of calcium in the case of insulinoma when the standard dose fails to detect such a tumor.

Adult↗

PubMed2002

Clinical implication of anti-p53 antibodies and p53-protein in pancreatic disease.

p53 gene mutations play an important role in the pathogenesis of pancreatic carcinomas. Anti-p53 antibodies and p53 protein have been detected in the sera of patients with pancreatic carcinomas. However, very little is known about the clinical significance of these p53 antibodies. We investigated the relationship between anti-p53 antibodies and the presence of p53 protein in cancer cells and the serum, as well as other clinical factors. Anti-p53 antibodies were detected in 19 (23%) of 82 pancreatic-duct-cell carcinomas, and in one (5%) of 21 cases of chronic pancreatitis. However, no antibodies were detected in mucin-producing tumors or in islet-cell tumors of the pancreas. The anti-p53 antibodies were detected in both early and advanced stages. In those patients undergoing surgical resection for pancreatic duct-cell carcinomas, the prognosis of patients who were negative for the anti-p53 antibodies was better than patients who were positive. Of the 11 cases that were positive for anti-53 antibodies, 8 (73%) were also positive for the immunohistochemical expression of p53 protein in cancer cells. However, there was no significant correlation between the presence of anti-p53 antibodies and the serum p53 protein levels. These results suggest that the benefits of measuring the anti-p53 antibody titier as a screening test to detect pancreatic carcinoma are limited, but the presence of anti-p53 antibodies predicts a poor prognosis for postoperative pancreatic carcinoma patients.

Aged↗

PubMed2002

Relationship between retention index in dual-phase (18)F-FDG PET, and hexokinase-II and glucose transporter-1 expression in pancreatic cancer.

UNLABELLED: Recently, some studies have shown that delayed scanning with (18)F-FDG PET may help to differentiate malignant from benign pancreatic lesions. However, no study has evaluated the relationship between temporal changes in (18)F-FDG uptake and expression of hexokinase or glucose transporter. METHODS: Twenty-one consecutive patients with pancreatic cancer were studied preoperatively by dual-phase (18)F-FDG PET, performed 1 and 2 h after injection of (18)F-FDG. The standardized uptake value (SUV) of the pancreatic cancer was determined, and the retention index (RI) (%) was calculated by subtracting the SUV at 1 h (SUV1) from the SUV at 2 h (SUV2) and dividing by SUV1. The percentages of cells strongly expressing hexokinase type-II (HK-II) and glucose transporter-1 (GLUT-1) were scored on a 5-point scale (1 = 0%-20%, 2 = 20%-40%, 3 = 40%-60%, 4 = 60%-80%, 5 = 80%-100%) by visual analysis of immunohistochemical staining of paraffin sections from the tumor specimens using anti-HK-II and anti-GLUT-1 antibody (HK-index and G-index, respectively). RESULTS: SUV2 (mean +/- SD, 5.7 +/- 2.6) was higher than SUV1 (5.1 +/- 2.1), with an RI of 8.5 +/- 11.0. Four cases of cancer, in which SUV2 showed a decline from SUV1, showed a low HK-index (1.8 +/- 1.1), whereas 4 cases with an RI of > or =20 and 13 cases with an intermediate RI (0-20) showed significantly higher HK-indices (4.3 +/- 0.7 and 3.1 +/- 1.5, respectively; P < 0.05). RI showed a positive correlation with HK-index, with an R(2) of 0.27 (P < 0.05), but no significant correlation with the G-index. SUV1 showed no relationship with the HK-index but showed a weak positive correlation with the G-index, with an R(2) of 0.05 (P = 0.055). CONCLUSION: These preliminary findings suggest that the RI obtained from dual-phase (18)F-FDG PET can predict HK-II expression and that the SUV (at 1 h) has a positive correlation with GLUT-1 expression but not with HK-II expression.

Adenocarcinoma↗

PubMed2002

[Current status of adjuvant therapy for pancreatic cancer].

Pancreatic cancer is considered to be one of the malignancies most resistant to therapy. It is characterized by early local invasion and distant spread. Therefore, resection with curative intent is limited to a very small proportion of patients. Even in these selected patients, long-term survival remains very poor because of liver and local recurrence. Therefore, control of occult liver metastasis and local residual tumor with perioperative radiotherapy and chemotherapy may provide some palliative benefits, and should have some impact on overall survival. However, none of the studies to date are considered definitive. Japanese pancreatic surgeons have developed a number of adjuvant therapies which theoretically could be good enough to prolong long term survival, however, they have not been tested in randomized controlled trials. Planning co-operative studies on this important issue in pancreatic cancer therapy is urgently needed.

Adult↗

PubMed2002

Trojan p16 peptide suppresses pancreatic cancer growth and prolongs survival in mice.

PURPOSE: The tumor suppressor gene p16INK4A is inactivated frequently in a large number of human cancers, and many investigators have attempted to restore the function of p16 using the p16 wild-type gene and viral vectors. In this study, we treated the tumor-bearing animals with the p16-derived synthetic peptide coupled with the Antennapedia carrier sequence, which we designated as Trojan p16 peptide. EXPERIMENTAL DESIGN: Injections (i.p.) of the Trojan p16 peptide (100 microg/mouse/day) were given for 3 weeks in the AsPC-1 and BxPC-3 s.c. tumor models. Tumor growth, histopathology, and TUNEL staining of the tumor and toxicity of the animals were evaluated. To examine its influence on the survival of tumor-bearing mice, Trojan p16 was administered in the AsPC-1 peritoneal dissemination model. RESULTS: In the AsPC-1 s.c. tumor model, a significant growth inhibition was obtained by the Trojan p16 treatment when compared with the three control treatments, i.e., vehicle, unconjugated form of p16, or Trojan peptide alone. Tumor growth inhibition was almost complete in the BxPC-3 tumor, a relatively slow growing tumor. Neither hematological cytotoxicity or body weight loss were observed. Histopathology of the BxPC-3 s.c. tumor in the Trojan p16 treatment group revealed marked vacuole formation and apoptotic death of cancer cells. In the AsPC-1 peritoneal dissemination model, the survival curve of mice treated with Trojan p16 was significantly longer than that of control. CONCLUSIONS: These results provide evidence that the Trojan p16 peptide system, a gene-oriented peptide coupled with a peptide vector, functions for experimental pancreatic cancer therapy.

Amino Acid Sequence↗

PubMed2002

Inhibitory effects of epigallocatechin-3-gallate on N-nitrosomethylbenzylamine-induced esophageal tumorigenesis in F344 rats.

The present study was conducted to assess the inhibitory effects of EGCG (epigallocatechin-3-gallate) on NMBA-induced rat esophageal tumorigenesis and to seek the potential mechanisms. In experiment I, 81 F344 rats were randomly divided into seven experimental groups according to the different regiments of NMBA 1 mg/kg subcutaneously (s.c.) and EGCG 4 mg/kg or 10 mg/kg orally or intraperitoneally (i.p.). The experiment was terminated at 24 weeks. In experiment II, 48 rats were allocated into two groups, each group contained 24 rats, in which the rats were injected with NMBA 1 mg/kg only or a combination of NMBA 1 mg/kg and EGCG 4 mg/kg i.p. Six rats from each group were sacrificed at the 12th, 16th, 20th and 24th week, respectively. The expression of cyclin D1 and cyclooxygenases (COX-2 and COX-1) was detected using semi-quantitative RT-PCR, and the production of prostaglandin E2 (PGE2) was measured by ELISA. In the groups which were treated with EGCG at a dose of 4 mg/kg i.p., or 10 mg/kg both orally and i.p., the mean number of tumors per rat was significantly reduced to 48, 56 and 61%, respectively (p<0.05). The incidence rate of esophageal carcinomas in the rats that were treated with EGCG 4 mg/kg i.p., was significantly lower than that in the rats which only received NMBA 1 mg/kg (p<0.05). The expression of cyclin D1 and COX-2, and the levels of PGE2 were also decreased by EGCG treatment. These results indicated that EGCG significantly inhibits the NMBA-induced rat esophageal carcinogenesis and it inhibitory effects may partly target cyclin D1 and COX-2 expression, and PGE2 production.

Animals↗