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T M Gress

Publications and source records attributed to T M Gress.

At least 19 recordsLinked to original sources
PubMed2005

A randomised phase II trial of weekly high-dose 5-fluorouracil with and without folinic acid and cisplatin in patients with advanced biliary tract carcinoma: results of the 40955 EORTC trial.

UNLABELLED: Previous small phase II trials have demonstrated that the combination of 5-fluorouracil (5FU) and cisplatin(CDDP) could have clinical activity in metastatic biliary tract cancer. This randomised phase II trial was designed to assess the activity and safety of a high-dose infusional weekly 5FU alone (HDFU) and the combination of 5FU, folinic acid (FA) and CDDP. Patients were included if they had histologically proven locally advanced or metastatic biliary tract carcinoma, World Health Organisation (WHO) performance status < or = 2, bilirubin <2 x upper normal limit, adequate haematological and renal functions and had not received prior chemotherapy, even in the adjuvant setting. TREATMENTS: Arm A (HDFU) consisted of cycles of 5FU 3 g/m(2) intravenously (i.v.), 24 h infusion, weekly, for 6 weeks, followed by 1 week rest, every 7 weeks; Arm B (5FU+FA+CDDP) consisted of cycles of 5FU 2.0 g/m(2) i.v. with folinic acid 500 mg/m(2), 2 h-infusion, weekly, for 6 weeks, followed by 1 week rest plus cisplatin 50 mg/m(2), once every two weeks, for 6 weeks, followed by 1 week rest, every 7 weeks. From February 1997 to June 1999, 58 patients were randomised (29 in each arm). Patients had a median age of 58 years in Arm A and 62 years in Arm B, locally advanced disease was present in 21% of the patients in Arm A and 11% in Arm B. WHO performance status of 0/1/2 was noted in 48%/45%/7% of the patients in Arm A and 54%/43%/4% in Arm B. In both arms, the most common metastatic sites were the liver and peritoneum. Twenty-eight patients were eligible in each arm and one patient did not start the allocated therapy in Arm B. The median number of cycles was 2 [range 1-12] in Arm A and 2 [range 1-6] in Arm B. Responses for the eligible patients who started their allocated therapy were as follows: Complete Response (CR) 0% in Arm A, 4% in Arm B, Partial Response (PR) 7% in Arm A, 15% in Arm B resulting in an overall response rate [95% CI] of 7.1% in Arm A [0.9-23.5%] and 19% [6.3-38.1%] in Arm B. Disease stabilisation was observed in 46% in Arm A and 44% in Arm B. National Cancer Institute of Canada (NCIC) grade 3-4 adverse events (% of patients in Arm A/Arm B) were neutropenia 4%/26%, thrombopenia 0%/7%, stomatitis 0%/4%, vomiting 7%/14%, diarrhoea 0%/11% and neurotoxicity 4%/0%. There was one early toxic death in Arm B. The median overall survival (OS) [95% CI] was in Arm A/Arm B: 5.0 [4.0-7.4] months/8.0 [5.8-11.8] months and the median progression-free survival (PFS) was 3.3 [1.7-4.7] months/3.3 [2.3-6.7] months. Cisplatin in combination with 5FU+FA showed a higher activity than HDFU, but was more toxic. These results are not sufficient to start a phase III trial. However, our group is planning a phase III trial comparing 5FU+folinic acid versus the same schedule+oxaliplatin a platinum analogue.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

Bacteria and bacterial toxins as therapeutic agents for solid tumors.

Patients with advanced solid tumors frequently relapse and succumb to their metastatic disease after developing resistance to conventional treatment modalities such as chemotherapy and radiotherapy. In these patients, novel strategies of targeting widespread tumors are urgently needed. The increasing knowledge of the underlying pathogenetic mechanisms has led to the identification of numerous molecules that are overexpressed in various tumors and accumulate at the cell surface. The use of genetically modified bacteria and their toxins targeting these surface molecules has emerged as a promising new treatment strategy in refractory cancers. This review focuses on bacterial toxins such as Diphtheria toxin (DT), Pseudomonas exotoxin A (PE) and Clostridium perfringens enterotoxin (CPE). In addition, the use of anaerobic bacteria such as Clostridium, Salmonella and Bifidobacterium spp. as drug-delivery systems targeting hypoxic tumor areas will be discussed as a new therapeutic modality of advanced solid tumors.

Animals↗
PubMed2003

KOC is a novel molecular indicator of malignancy.

The detection of malignant cells in fine-needle aspirates (FNA's) using marker genes is hampered by the fact that these markers are only expressed by certain malignancies or lack sensitivity and/or specificity. Here we report the results of a prospective pilot study examining the expression of KOC (KH-domain containing protein over expressed in cancer), a novel onco-foetal gene, in 76 patients who underwent fine-needle aspiration for further diagnosis of abdominal lesions, aszites, cysts or cerebrospinal fluid. Aspirates were examined by cytology and by a KOC RT-PCR assay. KOC expression was a highly sensitive and specific indicator of malignancy. The KOC assay could be useful to facilitate screening for malignant disease and to improve the diagnostic accuracy of FNAs.

Biopsy, Needle↗
PubMed2002

Reduced PTEN expression in the pancreas overexpressing transforming growth factor-beta 1.

PTEN is a candidate tumour suppressor gene and frequently mutated in multiple cancers, however, not in pancreatic cancer. Recently, it has been demonstrated that PTEN expression is regulated by TGF-beta1. Using TGF-beta1 transgenic mice (n=7) and wildtype littermates (n=6), as well as pancreatic tissues obtained from organ donors (n=10) and patients with pancreatic cancer (n=10), we assessed the expression of PTEN by means of immunohistochemistry and semiquantitative PCR analysis. In addition, PANC-1 cells were treated with TGF-beta1 in vitro and the levels of PTEN mRNA were determined in these cells. In human pancreatic cancers PTEN mRNA levels were significantly decreased (P<0.05). In addition, in the pancreas of TGF-beta1 transgenic mice the expression of PTEN was significantly reduced (P<0.01), as compared to wildtype littermates and incubation of PANC-1 cells with TGF-beta1 decreased PTEN mRNA levels after 24 h. Inasmuch as TGF-beta1 decreases PTEN expression in human pancreatic cancer cells and human pancreatic cancers overexpress TGF-beta1, the reduced expression of PTEN in pancreatic cancer may be mediated by TGF-beta1 overexpression. Thus, although PTEN is not mutated in pancreatic cancers, the reduction of its expression may give pancreatic cancer cells an additional growth advantage.

Animals↗
PubMed2002

The N34S mutation of SPINK1 (PSTI) is associated with a familial pattern of idiopathic chronic pancreatitis but does not cause the disease.

BACKGROUND: Mutations in the PRSS1 gene explain most occurrences of hereditary pancreatitis (HP) but many HP families have no PRSS1 mutation. Recently, an association between the mutation N34S in the pancreatic secretory trypsin inhibitor (SPINK1 or PSTI) gene and idiopathic chronic pancreatitis (ICP) was reported. It is unclear whether the N34S mutation is a cause of pancreatitis per se, whether it modifies the disease, or whether it is a marker of the disease. PATIENTS AND METHODS: A total of 327 individuals from 217 families affected by pancreatitis were tested: 152 from families with HP, 108 from families with ICP, and 67 with alcohol related CP (ACP). Seven patients with ICP had a family history of pancreatitis but no evidence of autosomal dominant disease (f-ICP) compared with 87 patients with true ICP (t-ICP). Two hundred controls were also tested for the N34S mutation. The findings were related to clinical outcome. RESULTS: The N34S mutation was carried by five controls (2.5%; allele frequency 1.25%), 11/87 (13%) t-ICP patients (p=0.0013 v controls), and 6/7 (86%) affected (p<0.0001 v controls) and 1/9 (11%) unaffected f-ICP cases. N34S was found in 4/108 affected HP patients (p=0.724 v controls), in 3/27 (11%) with wild-type and in 1/81 (1%) with mutant PRSS1, and 4/67 ACP patients (all p>0.05 v controls). The presence of the N34S mutation was not associated with early disease onset or disease severity. CONCLUSIONS: The prevalence of the N34S mutation was increased in patients with ICP and was greatest in f-ICP cases. Segregation of the N34S mutation in families with pancreatitis is unexplained and points to a complex association between N34S and another putative pancreatitis related gene.

Adult↗
PubMed2001

TGF-beta-induced invasiveness of pancreatic cancer cells is mediated by matrix metalloproteinase-2 and the urokinase plasminogen activator system.

TGF-beta strongly promotes local tumor progression in advanced epithelial tumors, though the underlying mechanisms are poorly understood. In the present study, we demonstrate the potential of TGF-beta to increase the invasiveness of the pancreatic cancer cell lines PANC-1 and IMIM-PC1. TGF-beta-induced tumor cell invasion occurred in a time-dependent manner, started after 12 hr and continued to increase even 48 hr after a single application of the growth factor. Blocking of secreted TGF-beta1 by application of neutralizing antibodies 24 hr after TGF-beta treatment completely prevented the sustained effects of TGF-beta on tumor cell invasion. Together with our previous observation that TGF-beta1 up-regulates its own expression in both cell lines, our data suggest that TGF-beta1 acts in an autocrine manner to maintain tumor cell invasion. As measured by Northern blot hybridization and zymography, TGF-beta treatment of PANC-1 and IMIM-PC1 cells resulted in strong up-regulation of expression and activity of both matrix metalloproteinase-2 (MMP-2) and the urokinase plasminogen activator (uPA) system. Treatment with MMP inhibitors or inhibitors of the uPA system caused significant reduction of TGF-beta-induced invasiveness in both cell lines. In contrast, expression and activity of MMP-2 and uPA as well as tumor cell invasiveness remained unaffected in cell lines with defects of the TGF-beta type II receptor (MiaPaca2) or the Smad4 gene (IMIM-PC2 and CAPAN-1). In these cell lines, TGF-beta also failed to auto-induce its own expression. In conclusion, our results suggest that TGF-beta1 is a strong promotor of pancreatic cancer progression. TGF-beta thereby acts in an autocrine manner to induce tumor cell invasion, which is mediated by MMP-2 and the uPA system.

Enzyme Activation↗
PubMed2001

Transforming growth factor beta1 treatment leads to an epithelial-mesenchymal transdifferentiation of pancreatic cancer cells requiring extracellular signal-regulated kinase 2 activation.

The aim of this study was to examine the effects of transforming growth factor (TGF) beta1 on the phenotype and the biological behavior of pancreatic cancer cell lines with and without mutations in the TGF-beta signaling pathway and to elucidate whether the Ras signaling cascade participates in mediating these effects of TGF-beta1. TGF-beta-responsive (PANC-1, COLO-357, and IMIM-PC1) and nonresponsive (CAPAN1 and IMIM-PC2) pancreatic cancer cell lines with activating mutations of the Ki-Ras oncogene were treated with 10 ng/ml TGF-beta1 over time. Phenotypic alterations were studied by electron and phase contrast microscopy and by immunohistochemistry and expression analyses of differentiation markers. The influence of TGF-beta on tumor cell scattering, migration, and invasion was determined. The role of the Ras-mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK) cascade in mediating TGF-beta-induced morphological and functional effects were studied by pretreatment with the MEK1 inhibitor PD 98059 and by measuring ERK2 activation using immune complex kinase assays. TGF-beta1 led to a reversible and time-dependent epithelial-mesenchymal transdifferentiation (EMT) in TGF-beta-responsive pancreatic cancer cell lines, characterized by a fibroblastoid morphology and an up-regulation of mesenchymal markers and a down-regulation of epithelial markers. EMT was associated with an increase in tumor cell migration, invasion, and scattering. In the responsive cell lines, TGF-beta1 induced a moderate but sustained activation of ERK2. EMT, the concomitant changes in gene expression, and the invasive and migratory potential were reduced or abolished by pretreatment with the selective MEK1 inhibitor. Thus, in TGF-beta-responsive pancreatic cancer cells with activating Ki-Ras mutations, TGF-beta1 treatment caused an EMT associated with a more invasive phenotype. Cross-talk with the Ras-MEK-ERK-signaling cascade appears to be essential for mediating these effects of TGF-beta1.

Cell Differentiation↗
PubMed2001

Loss of the Y chromosome is a frequent chromosomal imbalance in pancreatic cancer and allows differentiation to chronic pancreatitis.

In a study for the identification of genomic alterations in pancreatic cancer, representational difference analysis was used and led to the isolation of 2 distinct fragments, deleted on the Y chromosome in the xenografted tumor DNA of a male patient with an adenocarcinoma of the pancreas. Loss of Y chromosomal material was further studied in 11 pancreatic cancer cell lines of male origin, using PCR amplification of 5 sequence tagged sites (STSs) distributed along the Y chromosome; 8/11 cell lines exhibited a complete loss of the Y chromosome and 3 had deletions. To examine the status of the Y chromosome in situ, interphase FISH analysis was performed on paraffin sections from pancreatic carcinoma (n=7) and chronic pancreatitis (n=7) tissues, and the loss of Y-chromosomal STS-markers was studied in 6 xenograft tumors obtained from male pancreatic cancer patients. This analysis revealed that a loss of the Y chromosome occurs in vivo in primary pancreatic tumor cells, whereas the Y chromosome was intact in chronic pancreatitis. Our data suggest that loss of Y is a frequent event occurring in male pancreatic tumors. Although there is no evidence for a functional implication of Y chromosome loss, it effectively differentiates between a malignant and a benign condition as e.g. chronic pancreatitis. Thus, this genetic alteration may be of diagnostic use.

Animals↗
PubMed2001

Pancreatic function tests: when to choose, what to use.

Although techniques for high-resolution imaging of the pancreas are constantly being improved, the evaluation of pancreatic function remains crucial for the workup of pancreatic diseases. More than 20 direct and indirect tests are available for the assessment of pancreatic function. Measurement of fecal elastase-1 is recommended as the most suitable test for the initial assessment of pancreatic function. Among other techniques, the pancreolauryl test, and alternatively the BT-PABA (N-benzoyl-L-tyrosyl-p-aminobenzoic acid) or the (13)C-mixed-triglyceride test, yield the best sensitivity and specificity. Nevertheless, all indirect tests are of limited value in patients with mild to moderate impairment of pancreatic function. In these patients, the secretin-caerulein test remains the gold standard.

Ceruletide↗
PubMed2001

GRP-receptor-mediated signal transduction, gene expression and DNA synthesis in the human pancreatic adenocarcinoma cell line HPAF.

Bombesin-like peptides have been implicated as growth factors in various human cancers. Human adenocarcinoma cell lines (Capan-1, Capan-2, MiaPaCa-2 and HPAF) were tested to determine whether they express the gastrin-releasing peptide-preferring bombesin receptor (GRPR) and neuromedin B-preferring bombesin receptor (NMBR). Using RT-PCR the highest level of GRP receptor mRNA was found in HPAF cells. NMB receptor mRNA expression moderate in all cell lines investigated. We therefore selected the HPAF cell line to investigate whether bombesin treatment affects intracellular Ca(2+) ([Ca(2+)](i)), cAMP level, DNA synthesis as a measure of cell proliferation, and expression of three transcription factors: c-fos, c-myc and high mobility group protein IY (HMG-I(Y)).Bombesin administration led to an immediate increase in free intracellular Ca(2+) concentration ([Ca(2+)](i)) but did not change cAMP levels. The peptide also enhanced [(3)H]thymidine incorporation in HPAF cells (but not in the other cell lines), an effect that was concentration dependent, reaching 36 +/- 5% stimulation over control values at 24 h with an EC(50) of 2.27 x 10(-12) M. Furthermore, bombesin stimulated c-fos, c-myc and HMG-I(Y) expression in a time-dependent manner: the c-fos mRNA level increased dramatically in the first 30 min of exposure, then returned to basal level within 2 h, while the c-myc and HMG-I(Y) mRNA levels peaked at 2 h and 4h, respectively. All actions of bombesin were blocked by BME (D-Phe(6)-bombesin-(6-13)-methylester), a selective GRP receptor antagonist, but not by the NMB receptor antagonist BIM-23127 (D-Nal-cyclo[Cys-Tyr-D-Trp-Orn-Val-Cys]-Nal-NH(2)). We conclude that HPAF cells express mRNA for GRP receptors and that functional receptors are present in the cell membrane. The occupation of these receptors leads to a sequence of intracellular events involving rapid mobilization of intracellular Ca(2+), expression of c-fos, c-myc and HMG-I(Y) mRNA, and stimulation of cell proliferation. Conversely, although NMB receptor mRNA can be detected, its actual translation to functional receptors does not reach a detectable level.

Adenocarcinoma↗
PubMed2001

Claudin-4: a new target for pancreatic cancer treatment using Clostridium perfringens enterotoxin.

BACKGROUND & AIMS: Recently, several members of the claudin family have been identified as integral constituents of tight junctions. Using expression profiling, we previously found claudin-4 to be overexpressed in pancreatic cancer. Because claudin-4 has been described as a receptor for the cytotoxic Clostridium perfringens enterotoxin (CPE), we investigated the effect of CPE on pancreatic cancer cells. METHODS: Expression of claudin-4 was analyzed by Northern blots. In vitro toxicity of CPE was determined by trypan blue exclusion and the (86)Rb-release assay. The in vivo effect of CPE was studied in claudin-4-expressing nude mouse xenografts of the Panc-1 cell line. RESULTS: Expression analyses showed that claudin-4 was overexpressed in most pancreatic cancer tissues and cell lines and several other gastrointestinal tumors. CPE led to an acute dose-dependent cytotoxic effect, restricted to claudin-4-expressing cells and dependent on claudin-4 expression levels. Furthermore, transforming growth factor beta was identified as a negative modulator of both claudin-4 expression and susceptibility to CPE. In vivo, intratumoral injections of CPE in Panc-1 xenografts led to large areas of tumor cell necrosis and significant reduction of tumor growth. CONCLUSIONS: Our findings suggest that targeting claudin-4-expressing tumors with CPE represents a promising new treatment modality for pancreatic cancer and other solid tumors.

Adenocarcinoma↗
PubMed2001

Biglycan is overexpressed in pancreatic cancer and induces G1-arrest in pancreatic cancer cell lines.

BACKGROUND & AIMS: Biglycan (PG-I), a component of the extracellular matrix (ECM), is overexpressed in pancreatic cancer. To determine possible matrix-tumor interactions, we investigated the effects of PG-I on pancreatic cancer. METHODS: PG-I expression in cell lines and tissue samples was examined by Northern blot and immunofluorescence. The effect of PG-I on proliferation was determined by measuring activity of Ras, ERK, Rb, [(3)H]-thymidine incorporation, and cell cycle analysis. Expression of cyclin A, B1, D1, E1, G1, PCNA, p21, and p27 was analyzed by Northern and Western blots. RESULTS: PG-I was overexpressed in the ECM of pancreatic cancer samples compared with normal pancreas or chronic pancreatitis tissues. Addition of transforming growth factor (TGF)-beta induced PG-I expression in HFL and HFFF2 fibroblasts as well as in the pancreatic cancer cell line PANC-1. PG-I inhibited growth of both TGF-beta-responsive and TGF-beta-unresponsive pancreatic cancer cells by inducing G1-arrest, which is accompanied by an increase of p27 and reduction of cyclin A and proliferating cell nuclear antigen. Furthermore, endogenous Ras and ERK activation was partly reduced by PG-I in vitro. CONCLUSIONS: The ECM protein PG-I inhibits growth by arresting pancreatic cancer cells in G1 and may be part of a host defense mechanism aimed at slowing down pancreatic tumor progression.

Adult↗
PubMed2001

Use of DNA arrays/microarrays in pancreatic research.

In recent years, enormous technical advances in experimental protocols as well as robotic and bioinformatic techniques have allowed DNA array/microarray technology to emerge as the leading technology in the field of functional, disease-related genome analysis. Multiple applications exist for DNA arrays/microarrays including comparative genomic analysis to identify chromosomal imbalances (Matrix-CGH), the study of mutations and genetic polymorphisms, and the study of gene expression (expression profiling). Expression profiling is the most widely used application of DNA array/microarray technology and allows to measure gene expression of thousands of genes simultaneously. The present review describes the basic principles of expression profiling analyses and outlines some applications in pancreatic cancer research.

Humans↗
PubMed2000

Role of the MEN1 tumour suppressor gene in human ductal pancreatic cancer.

MEN1 is a novel tumour suppressor gene involved in the etiology of sporadic endocrine pancreatic tumours. Based on common ontogenetic features of both tissues, we analyzed the role of MEN1 in ductal pancreatic cancer. Wild type MEN1 mRNA expression, but no mutations within the MEN1 coding sequence or MEN1 promoter region were detected in human pancreatic adenocarcinoma tissues and carcinoma cell lines, using sensitive single-strand conformational polymorphism-heteroduplex and sequencing analyses. Thus, human pancreatic cancer does not seem to require inactivation of the MEN1 tumour suppressor pathway.

Carcinoma, Ductal, Breast↗
PubMed2000

A novel transmembrane serine protease (TMPRSS3) overexpressed in pancreatic cancer.

We report the characterization of a novel serine protease of the chymotrypsin family, recently isolated by cDNA-representational difference analysis, as a gene overexpressed in pancreatic cancer. The 2.3-kb mRNA of the gene, named TMPRSS3, is strongly expressed in a subset of pancreatic cancer and various other cancer tissues, and its expression correlates with the metastatic potential of the clonal SUIT-2 pancreatic cancer cell lines. The deduced polypeptide sequence consists of 437 amino acids and exhibits all of the structural features characteristic of serine proteases with trypsin-like activity. TMPRSS3 is membrane bound with a NH2-terminal signal-anchor sequence and a glycosylated extracellular region containing the serine protease domain. Thus, TMPRSS3 is a novel membrane-bound serine protease overexpressed in cancer, which may be of importance for processes involved in metastasis formation and tumor invasion.

Amino Acid Sequence↗
PubMed2000

Role of MT-MMPs and MMP-2 in pancreatic cancer progression.

Activation of matrix metalloproteinase-2 (MMP-2) by the membrane-type matrix metalloproteinases (MT-MMPs) has been associated with tumor progression. In the present study, we examined the role of MMP-2 and its activators MT1-MMP, MT2-MMP and MT3-MMP in pancreatic tumor cell invasion and the development of the desmoplastic reaction characteristic of pancreatic cancer tissues. Northern blot analyses revealed that transcript levels of MT1-MMP and MT2-MMP, but not MT3-MMP, were enhanced in pancreatic cancer tissues (n = 18) compared with both chronic pancreatitis (n = 9) and healthy pancreas (n = 9). A good correlation was found between MT1-MMP and both MMP-2 expression (p < 0.01) and activity in pancreatic cancer tissues. In addition, expression and activation of MMP-2 were strongly associated with the extent of the desmoplastic reaction in pancreatic cancer tissues. Invasion assays showed a good correlation between MMP-2 expression and activity and the invasive potential of pancreatic cancer cell lines. In cell lines with high levels of MMP-2 expression and activity, the MMP inhibitor Batimastat led to significant reduction of the number of invading cells. Our results suggest that MT1-MMP is involved in the progression of pancreatic cancer via activation of MMP-2. MMP-2 itself plays an important role in tumor cell invasion and appears to be associated with the development of the characteristic desmoplastic reaction in pancreatic cancer.

Adenocarcinoma↗