Balance of expression of genes coding for extracellular matrix proteins and extracellular matrix degrading proteases in chronic pancreatitis

Chronic pancreatitis is characterized by proliferation of the extracellular matrix and by increased deposition of interstitial extracellular matrix proteins (collagens type I and III, fibronectin). In this study we analyzed the balance of expression of mRNAs encoding extracellular matrix components (collagens I, III and IV, laminin, fibronectin), extracellular matrix degrading metalloproteinases (MMP-1, -2 and -3) and tissue inhibitors of metalloproteinases (TIMP-1 and -2) in chronic pancreatitis (n = 8) and control pancreas (n = 7) by northern blot analysis. Transcripts for MMP-1 (interstitial collagenase), MMP-3 (stromelysin) and TIMP-1 were not detectable in chronic pancreatitis and control tissues. Steady-state levels of transcripts encoding extracellular matrix proteins, MMP-2 (72 kDa collagenase IV) and TIMP-2 were enhanced in 7 out of 8 chronic pancreatitis tissue samples and showed a large degree of variation between individual patients. Transcript levels could not be correlated to the histologically detectable degree of inflammation and fibrosis or to the total amount of deposited collagen protein, which was high in all chronic pancreatitis tissue samples as determined by a standard colorimetric procedure. Increased steady state levels of transcripts encoding extracellular matrix proteins or extracellular matrix degrading proteases may thus reflect the activity of processes involved in the remodeling of the gland during chronic inflammation. The precise role of overexpression of MMP-2 and its inhibitor TIMP-2 will have to be elucidated in further studies.

Carcinoid of the ampulla of Vater. Clinical characteristics and morphologic features

BACKGROUND

Carcinoid tumors of the gastrointestinal tract are most common localized in the appendix, followed by the small intestine, the rectum, and the stomach. The localization of these tumors at the ampulla of Vater is extremely seldom.

METHODS

In the present study the authors describe two patients with carcinoid tumors of the ampulla Vater and review 71 previously published cases.

RESULTS

Most patients presented with jaundice, but without carcinoid syndrome. Because the tumor grows submucosally, preoperative diagnosis was correct only in 15%. Most tumors were around 2 cm in size. Metastasis to lymph nodes and/or liver was present in 45%. Standard treatment is Whipple resection or local excision in small tumors.

CONCLUSIONS

Carcinoid tumors of the ampulla of Vater are an extremely rare clinical entity. Generally, the prognosis is good with a 5-year survival period of 90%.

Cripto, a member of the epidermal growth factor family, is over-expressed in human pancreatic cancer and chronic pancreatitis

Cripto is a 188 amino-acid protein containing a central segment that shares amino-acid sequence homology with epidermal growth factor (EGF) and transforming growth factor alpha (TGF-alpha). The EGF receptor, EGF and TGF-alpha are expressed in the normal human pancreas, and are over-expressed in human pancreatic cancer. Therefore, in the present study we sought to determine whether cripto is found in the normal human pancreas and whether its expression is altered in pancreatic cancer. Because chronic pancreatitis (CP) is associated with interstitial fibrosis similar to that observed in pancreatic cancer, we also examined cripto expression in pancreatic tissues from patients with CP. In the normal pancreas, cripto immunoreactivity was found at moderate levels in most ductal cells and was present very faintly in a rare acinar cell. In 26 of 58 pancreatic cancers, cripto immunoreactivity was present in many cancer cells. Its presence was associated with advanced tumor stage, but not with shorter post-operative survival. Cripto was also present in acinar and ductal cells adjacent to the cancer cells, and in many ductal atrophic acinar cells in the CP samples. Northern blot analysis revealed a marked increase in cripto mRNA levels in the cancer and CP samples. By densitometry, there was a 11- and 4-fold increase in cripto mRNA levels in pancreatic cancer and CP respectively. Southern blot analysis did not reveal an increase in gene copies encoding cripto either in cancer or in CP. These findings indicate that cripto expression may contribute to disease progression in pancreatic cancer, and implicate cripto in the histopathological alterations that occur in the pancreas both in cancer and in CP.

Differential expression of heat shock proteins in pancreatic carcinoma

In the present study we sought to determine by Northern blot analysis and mRNA in situ hybridization whether gene expression of heat shock proteins (HSPs) (HSP 89 alpha, HSP 89 beta, HSP 70, and ubiquitin) is altered in pancreatic carcinoma, compared to control tissues (normal pancreas and chronic pancreatitis tissue). HSP 89 alpha was selectively overexpressed in pancreatic carcinoma, and tumor cells were shown to contain the largest amount of HSP 89 alpha mRNA. Steady state levels of HSP 70 mRNA were increased in pancreatic carcinoma (tumor and connective tissue cells) and in chronic pancreatitis (connective tissue cells and residues of exocrine acinar cells). HSP 89 beta and ubiquitin B were constitutively expressed at high levels in pancreatic tissue from all three groups; HSP 89 beta mRNA was found in cells of parenchymal and stromal origin. A strong correlation was found between the expression of HSP 70 and the expression of transforming growth factor beta 1. The finding that HSPs are differentially expressed in pancreatic cancer, compared to normal pancreas and chronic pancreatitis tissue, and the cancer specificity of HSP 89 alpha suggest that HSPs play a specific role in the pathogenesis of pancreatic cancer, e.g., by participating in regulatory processes or in tumor immunity, as proposed previously.

Role of somatostatin and its analogues in the treatment of acute and chronic pancreatitis

Acute pancreatitis is caused by the activation of digestive enzymes in the pancreas and a possible treatment, therefore, is the inhibition of enzyme secretion. This approach is somewhat controversial, however, as it is not clear whether pancreatic secretion continues to occur during the course of acute pancreatitis. Animal studies show an appreciable reduction of secretion in the inflamed pancreas, but studies in humans are not conclusive. The use of somatostatin or its analogue, octreotide, has been investigated in several clinical studies. A meta analysis of six individual studies in which somatostatin was given for acute pancreatitis showed that somatostatin significantly reduces mortality. A trial in patients with moderate to severe acute pancreatitis showed a lower rate (although not statistically significant) of complications in patients treated with 3 x 200 and 3 x 500 micrograms/day octreotide, compared with controls and patients receiving a lower dose of octreotide. A further study showed a significant reduction in patient controlled analgesics in patients treated with octreotide compared with controls. Pain is the important clinical symptom of chronic pancreatitis, possibly resulting from an increased intraductal pressure during secretion. The effect on pain of the inhibition of pancreatic secretion by octreotide has been investigated in two studies. One showed no significant reduction in pain after treatment with octreotide for three days. In the other, in which octreotide was used for three weeks, significantly less pain and analgesic use was recorded during octreotide treatment than during placebo. The most common complication of chronic pancreatitis is the formation of pseudocysts. There is some evidence that octreotide may be useful in their treatment.

Inhibition of pancreatic secretion under long-term octreotide treatment in humans

The somatostatin analogue octreotide (SMS 201-995) is a potent inhibitor of human exocrine pancreatic secretion. In the present study we analyzed the effect of octreotide (3 x 100 micrograms, daily) given over a time period of 7 days on hormone-stimulated exocrine pancreatic secretion in 6 healthy volunteers using a secretin-ceruletide test. The secretin-ceruletide test was carried out before, following the first injection of octreotide (day 1) and after a 7-day treatment with 3 x 100 micrograms octreotide daily. Duodenal fluid was collected over 30 min without stimulation, over 60 min following a bolus injection of 1 U/kg body weight secretin, and over 60 min during a continuous infusion of secretin and ceruletide. Following the first injection of octreotide and following 7 days of octreotide treatment secretin/ceruletide-stimulated amylase secretion was significantly reduced. Trypsin and chymotrypsin secretion was significantly reduced after the first injection of octreotide when pancreatic secretion was stimulated by secretin and ceruletide simultaneously. However, secretin and ceruletide-induced trypsin and chymotrypsin secretion was not inhibited after 7 days of octreotide treatment. Baseline, secretin and secretin/ceruletide-stimulated bicarbonate output were not influenced by octreotide either following the first injection of octreotide or the 7 days' treatment. Octreotide is a potent inhibitor of secretin/ceruletide-stimulated pancreatic amylase, trypsin and chymotrypsin secretion. However, following a 7-day treatment with octreotide this inhibition is only persistent for pancreatic amylase secretion.

Increased expression of acidic and basic fibroblast growth factors in chronic pancreatitis

Acidic fibroblast growth factor (aFGF) and basic fibroblast growth factor (bFGF) belong to a family of mitogenic polypeptides that are involved in cellular proliferation and differentiation. In this study we investigated the potential role of aFGF and bFGF in chronic pancreatitis (CP), a fibrotic condition associated with acinar cell dedifferentiation and atrophy, and fibroblastic proliferation. By immunohistochemistry, aFGF and bFGF were abundant in pancreatic ductal and acinar cells in pancreatic tissues from CP patients. Immunoblotting with the same highly specific monoclonal antibodies demonstrated a marked increase in aFGF and bFGF in pancreatic homogenates from CP patients by comparison with the normal pancreas. Northern blot analysis indicated that, by comparison with normal controls, 16 of 21 CP tissues exhibited a 14-fold increase in aFGF mRNA levels, and 19 of 21 CP tissues exhibited a 15-fold increase in bFGF mRNA levels. In situ hybridization confirmed that this overexpression occurred in ductal and acinar cells, and indicated that both mRNA moieties colocalized with their respective proteins. These findings suggest that aFGF and bFGF may either be involved in the pathobiological mechanisms that occur in CP, or that their overexpression may be the consequence of other perturbations that occur in this disorder.

Octreotide in the treatment of acute pancreatitis: results of a unicenter prospective trial with three different octreotide dosages

Acute necrotizing pancreatitis is still associated with high morbidity and mortality. In this prospective clinical trial, we analyzed the effect of octreotide in patients with acute pancreatitis. Eight patients received either 3 x 100, 3 x 200 or 3 x 500 micrograms octreotide subcutaneously per day over a period of 10 days. The complication rate was lower in the group of patients who received 3 x 200 or 3 x 500 micrograms octreotide than in the control group and the group of patients who received the dosis of 3 x 100 micrograms octreotide per day. The results of this study are promising and must be validated in a controlled clinical trial with octreotide in a larger patient population.

Role of octreotide in the treatment of pancreatic cancer

Prognosis in patients with advanced pancreatic cancer is dismal. There has been no effective therapy for these patients so far. Somatostatin and its analogues have been proven to be potent inhibitors of experimental pancreatic cancer. Tumor inhibition is supposed to be mediated directly by somatostatin-binding sites or indirectly by suppression of growth factors. In two trials the value of the new somatostatin analogue octreotide in a low-dose (3 x 100 micrograms/day) and a high-dose (3 x 2,000 micrograms/day) protocol was evaluated in patients with advanced pancreatic cancer. Median survival of the patients with a low-dose protocol was 3 months. However, the treatment of pancreatic cancer with a high-dose protocol revealed a median survival of 6 months and stable disease in 4/10 patients. According to quality of life scoring 4 patients showed values comparable to healthy controls. Octreotide therapy with a high-dose protocol is a promising experimental therapeutic approach to advanced pancreatic cancer.

Potential role of somatostatin and octreotide in the management of acute pancreatitis

The pathophysiology of acute pancreatitis remains controversial. Activation of digestive enzymes in the pancreas may play an important role in the course of this disease. Therefore, the inhibition of enzyme secretion may be a possible treatment concept. However, it is not clear whether pancreatic secretion continues during the course of acute pancreatitis. In the present paper experimental and clinical studies are reviewed to evaluate the effect of somatostatin and octreotide treatment in acute pancreatitis.

Enhanced expression of transforming growth factor beta isoforms in pancreatic cancer correlates with decreased survival

BACKGROUND

Transforming growth factor beta s (TGF-beta s) constitute a family of bifunctional polypeptide growth factors that either inhibit or stimulate cell proliferation. Perturbations in TGF-beta expression and function may lead to loss of negative constraints on cell growth. In this study, we examined TGF-beta expression in human pancreatic cancer.

METHODS

The distribution of TGF-beta isoforms in 60 human pancreatic cancers was examined using immunohistochemical, Northern blot, and in situ hybridization techniques.

RESULTS

Immunohistochemical analysis showed the presence of TGF-beta 1 (47% of tumors), TGF-beta 2 (42% of tumors), and TGF-beta 3 (40% of tumors) in the cancer cells. The presence of TGF-beta 2 was associated with advanced tumor stage (P < 0.05). Furthermore, there was a significant correlation between the absence of TGF-beta s in the tumors and longer postoperative survival. Northern blot analysis indicated that, by comparison with the normal pancreas, pancreatic adenocarcinomas showed 11- (P < 0.001), 7- (P < 0.05), and 9-fold (P < 0.001) increases in the messenger RNA (mRNA) levels encoding TGF-beta 1, TGF-beta 2, and TGF-beta 3, respectively. By in situ hybridization, these mRNA moieties colocalized with their respective proteins in the cancer cells.

CONCLUSIONS

These findings show that human pancreatic cancers show increased levels of TGF-beta isoforms and enhanced TGF-beta mRNA expression and suggest that the presence of TGF-beta s in pancreatic cancer cells may contribute to disease progression.

Overexpression of acidic and basic fibroblast growth factors in human pancreatic cancer correlates with advanced tumor stage

Acidic fibroblast growth factor (aFGF) and basic FGF (bFGF) are mitogenic polypeptides that may contribute to cancer cell proliferation. In the present study we examined aFGF and bFGF expression in human pancreatic cancer. Northern blot analysis of total RNA isolated from 12 pancreatic cancers revealed elevated aFGF and bFGF mRNA levels in 12 and 10 samples, respectively, by comparison with the normal human pancreas. Immunostaining demonstrated the presence of aFGF and bFGF in many cancer cells and in the atrophic acini and ducts adjacent to the cancer cells, but to a much lesser extent in the surrounding fibroblasts. By in situ hybridization, both mRNA moieties colocalized with their respective proteins and were abundant in many cancer cells. Immunoblotting confirmed that cancer tissues with increased aFGF and bFGF immunoreactivity contained elevated levels of both proteins. To determine the significance of aFGF and bFGF expression in the pancreatic cancer cells, immunohistochemical analysis of 78 human pancreatic carcinomas was performed. aFGF and bFGF immunoreactivity was present in the cancer cells in 47 (60%) and 44 (56%) of the tumors, respectively. There was a significant correlation between the presence of either aFGF or bFGF in the cancer cells and advanced tumor stage, and the presence of bFGF and shorter patient survival. These data suggest that aFGF and bFGF are overexpressed in a significant proportion of human pancreatic carcinoma cells and that this overexpression may contribute to disease progression.

Aberrant expression of type I fibroblast growth factor receptor in human pancreatic adenocarcinomas

Acidic and basic fibroblast growth factors are mitogenic polypeptides that are overexpressed in pancreatic cancer. To determine whether fibroblast growth factors may exert direct effects on pancreatic cancer cells in vivo, we compared the expression of the high-affinity type I fibroblast growth factor receptor (FGFR-1) in human pancreatic tissues. In the normal pancreas, FGFR-1 immunostaining was seen mainly in acinar cells. In pancreatic cancers, FGFR-1 was abundant in ductal-like cancer cells which also exhibited many FGFR-1 mRNA in situ hybridization grains. Analysis by the polymerase chain reaction and RNase protection revealed that the 2-immunoglobulin-like and the 3-immunoglobulin-like forms of FGFR-1 were expressed in all tissue samples, and that the 2-immunoglobulin-like form was overexpressed in the cancer tissues by comparison with the normal tissues. These findings suggest that the 2-immunoglobulin-like form of FGFR-1 may contribute to aberrant autocrine and paracrine pathways in pancreatic cancer.

Overexpression of HER2/neu oncogene in human pancreatic carcinoma

The HER2/neu oncogene encodes a transmembrane protein that possesses intrinsic tyrosine kinase activity. Its overexpression has been associated with the malignant phenotype. In this study we examined HER2/neu expression in the normal and cancerous human pancreas. In the normal pancreas HER2/neu immunostaining was observed in acinar and ductal cells. HER2/neu immunoreactivity was expressed in 34 of 76 (45%) pancreatic carcinomas. There was a significant correlation between tumors with well-differentiated histology and HER2/neu expression. Northern blot analysis demonstrated HER2/neu mRNA expression in the normal pancreas and in situ hybridization confirmed its distribution in both acinar and ductal cells. In cancer tissues Northern blot analysis indicated that HER2/neu mRNA levels were elevated in 13 of 25 (52%) of the tumors in comparison with the normal tissues. In addition, in situ hybridization demonstrated a strong but heterogenous distribution of mRNA grains in these tumors. Southern blot analysis did not demonstrate HER2/neu gene amplification in any of the tumors. These data indicate that the HER2/neu protein is synthesized in the normal exocrine pancreas and is frequently overexpressed in well-differentiated adenocarcinomas of the pancreas as a result of increased HER2/neu mRNA levels.

Low-dose octreotide treatment is not effective in patients with advanced pancreatic cancer

Octreotide (SMS 201-995), a long-acting somatostatin analogue, has been shown to decelerate growth of human pancreatic cancer in vitro and in vivo. We analyzed the efficacy of octreotide treatment in 22 patients (14 men, 8 women) with histologically verified ductal pancreatic cancer. All patients had advanced tumor stages (stage III: 13 patients; stage IV: 9 patients). Octreotide was given by self-administered subcutaneous injection (3 x 100 micrograms/day). When there was evidence of tumor progression, the dose of octreotide was increased to 3 x 200 micrograms/day. A monthly follow-up, including clinical status, CT scan or ultrasonography, and tumor marker carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 determination was carried out. There were no severe side effects apart from slight burning sensation at the injection site. No partial or complete remission was seen. Eighteen patients showed tumor progression with a median survival time of 17 weeks (range 3-42 weeks). In three patients a "no change" evaluation with a median survival time of 46 weeks (range 40-68 weeks) was registered. In these three patients the serum tumor markers CA 19-9 and CEA did not show an increase to more than twice the baseline value during this time. One patient discontinued the octreotide treatment because of tumor progression. The results of the analysis indicate that low-dose octreotide treatment is not effective in patient suffering from advanced tumor stages of pancreatic cancer.

Enhanced expression of the type II transforming growth factor beta receptor in human pancreatic cancer cells without alteration of type III receptor expression

We have recently found that human pancreatic adenocarcinomas exhibit strong immunostaining for the three mammalian transforming growth factor beta (TGF-beta) isoforms. These important growth-regulating polypeptides bind to a number of proteins, including the type I TGF-beta receptor (T beta R-I), type II TGF-beta receptor (T beta R-II), and the type III TGF-beta receptor (T beta R-III). In the present study we sought to determine whether T beta R-II and T beta R-III expression is altered in pancreatic cancer. Northern blot analysis indicated that, by comparison with the normal pancreas, pancreatic adenocarcinomas exhibited a 4.6-fold increase (P < 0.01) in mRNA levels encoding T beta R-II. In contrast, mRNA levels encoding T beta R-III were not increased. In situ hybridization showed that T beta R-II mRNA was expressed in the majority of cancer cells, whereas mRNA grains encoding T beta R-III were detectable in only a few cancer cells and were present mainly in the surrounding stroma. These findings suggest that enhanced levels of T beta R-II may have a role in regulating human pancreatic cancer cell growth, while T beta R-III may function in the extracellular matrix.

p53 mutations are common in pancreatic cancer and are absent in chronic pancreatitis

Pancreatic expression of the p53 tumor suppressor gene was studied in pancreatic adenocarcinomas and chronic pancreatitis. By immunohistochemistry, 16 of 34 (47%) cancers and none of the 24 chronic pancreatitis samples revealed nuclear staining. Sequence analysis indicated that 8 of 24 (33%) cancers were mutated for the p53 gene. Point substitutions occurred at codons 35, 105, 133, 213, 213, 258, and 299. A three base-pair in-frame insertion was identified between codons 261 and 262. None of 8 chronic pancreatitis samples exhibited p53 gene mutations. These data support a role for p53 gene alterations in human pancreatic cancer, and suggest that loss of its regulatory functions may constitute one of the differences between pancreatic cancer and chronic pancreatitis.

Synthesis and expression of transforming growth factor beta-1, beta-2, and beta-3 in the endocrine and exocrine pancreas

The actions of transforming growth factor-beta isoforms as potent regulators of growth and differentiation have led to the examination of their presence in the human pancreas. The cellular localization of TGF-beta 1, TGF-beta 2, and TGF-beta 3 was assessed in the normal human pancreas by using immunohistochemical and in situ hybridization techniques. Although cytoplasmic immunoreactivity for TGF-beta 1, TGF-beta 2, and TGF-beta 3 was found in islet cells, acinar cells, and ductal cells, a differential immunostaining pattern for TGF-beta isoforms was observed. In the endocrine pancreas, the islet cells demonstrated diffuse cytoplasmic immunostaining for TGF-beta 1, TGF-beta 2, and TGF-beta 3. However, only TGF-beta 2 and TGF-beta 3 exhibited an intense pattern of immunostaining in a few endocrine cells. Most of the positive islet cells coexpressed insulin. In contrast, in the exocrine pancreas, a greater number of acinar cells showed immunoreactivity for TGF-beta 1 than for TGF-beta 2 and TGF-beta 3. In the ductal cells, all three TGF-beta isoforms showed a similar intensity and pattern of immunostaining and were observed more frequently in the smaller distal ductules than in the larger pancreatic ducts. TGF-beta 1 and TGF-beta 3, but not TGF-beta 2, immunostaining was detected strongly in the smooth muscle cells and weakly in the endothelial cells of the blood vessels, whereas the fibroblasts of the interstitium were completely negative. In situ hybridization revealed that mRNA encoding all three TGF-beta isoforms colocalized with their respective proteins in islets, acinar cells, and ductal cells. In contrast, mRNA expression was absent in the smooth muscle cells and endothelium of the vessels. These results suggest that TGF-beta isoforms may act by both autocrine and paracrine mechanisms in the pancreas. The differential pattern of expression observed for each TGF-beta isoform implies unique roles for these proteins in the regulation of the endocrine and exocrine pancreas.

Coexpression of epidermal growth factor receptor and ligands in human pancreatic cancer is associated with enhanced tumor aggressiveness

Immunohistochemical analysis for the epidermal growth factor receptor (EGFR), EGF and transforming growth factor-alpha (TGF-alpha) was performed in 87 human pancreatic carcinomas. Expression frequencies for EGFR, EGF, and TGF-alpha were 43%, 46% and 54%, respectively. Coexpression of the receptor and at least one of its ligands occurred in 38% of the tumors, and correlated with large tumor size, advanced clinical staging, and decreased survival period. In situ hybridization revealed that the respective mRNAs were also overexpressed in the carcinomas. These findings suggest that coexpression of EGFR and its ligands may contribute to the aggressiveness of human pancreatic cancer.

Inhibition of pancreatic secretion to prevent postoperative complications following pancreatic resection

Major pancreatic resection still nowadays carries a considerable risk for morbidity and even mortality. Complications occurring after pancreatic surgery are chiefly linked with exocrine pancreatic secretion. Therefore to inhibit exocrine pancreatic secretion perioperatively, seems to be a promising concept in the prevention of complications following pancreatic resection. The hormone somatostatin and its synthetic analogue octreotide have been demonstrated to inhibit exocrine pancreatic secretion profoundly, particularly the secretion of proteases is decreased. In a randomized placebo-controlled multicentric and double blind trial we analysed the role of octreotide in the prevention of postoperative complications after major pancreatic surgery. A significant reduction of complications (fistula, abscess, fluid collection, sepsis, pulmonary insufficiency, postoperative acute pancreatitis) could be demonstrated in patients receiving octreotide (3 x 100 micrograms per day sc.). The effect of octreotide was particularly true in patients undergoing a Whipple resection for cancer.