Treatment of duct carcinoma of the pancreas with the LH-RH analogue buserelin

Head and Body/Tail Pancreatic Carcinomas Are Not the Same Tumors

The association between pancreatic ductal adenocarcinoma (PDAC) location (head vs. Body/Tail (B/T)) and clinical outcome remains controversial. We collected clinicopathological and gene expression data from 249 resected PDAC samples from public data sets, and we compared data between 208 head and 41 B/T samples. The 2-year overall survival (OS) was better for the head than for the B/T PDACs (44 vs. 27%, p = 0.043), especially when comparing tumors with similar TNM classification (T3/4N0M0: 67% vs. 17%, p = 0.002) or from the same molecular class (squamous subtype: 31% vs. 0%, p < 0.0001). Bailey's molecular subtypes were differentially distributed within the two groups, with the immunogenic subtype being underrepresented in the "B/T" group (p = 0.005). Uni- and multivariate analyses indicated that PDAC anatomic location was an independent prognostic factor. Finally, the supervised analysis identified 334 genes differentially expressed. Genes upregulated in the "head" group suggested lymphocyte activation and pancreas exocrine functions. Genes upregulated in the "B/T" group were related to keratinocyte differentiation, in line with the enrichment for squamous phenotype. We identified a robust gene expression signature (GES) associated with B/T PDAC location, suggesting that head and B/T PDAC are different. This GES could serve as an indicator for differential therapeutic management based on PDAC location.

Prognostic value of PDL1 expression in pancreatic cancer

Pancreatic cancer is one of the most aggressive human cancers. PD1/PDL1-inhibitors recently showed promising results in different cancers with correlation between PDL1 tumor expression and responses. Expression of programmed cell death receptor ligand 1 (PDL1) has been scarcely studied in pancreatic cancer. In this retrospective study, we analyzed PDL1 mRNA expression in 453 clinical pancreatic cancer samples profiled using DNA microarrays and RNASeq. Compared to normal pancreatic samples, PDL1 expression was upregulated in 19% of cancer samples. Upregulation was not associated with clinicopathological features such as patients' age and sex, pathological type, tumor size, lymph node status, and grade, but was associated with shorter disease-free survival and overall survival in multivariate analyses. Analysis of correlations with biological parameters showed that PDL1 upregulation was associated with some degree of lymphocyte infiltration and signs of anti-tumor T-cell response, but to a lesser extent than what has been reported in breast cancer and GIST. PDL1-up pancreatic cancers displayed profiles of lymphocyte exhaustion, were more enriched in inhibitory molecules and pro-tumor populations (Tregs with upregulation of FOXP3 and IL10, myeloid-derived suppressor cells with upregulation of CD33 and S100A8/A9), and demonstrated a down-modulation of most MHC class I members (HLA-A/B/C, HLA-E/F/G) suggestive of a defect in antigen processing and presentation. In conclusion, our results suggest that PDL1 expression might refine the prediction of metastatic relapse in operated pancreatic cancer, and that PD1/PDL1 inhibitors might reactivate inhibited T-cells to increase the anti-tumor immune response in PDL1-upregulated tumors.

Cadherin-11 Is a Cell Surface Marker Up-Regulated in Activated Pancreatic Stellate Cells and Is Involved in Pancreatic Cancer Cell Migration

Chronic pancreatitis is a prominent risk factor for the development of pancreatic ductal adenocarcinoma. In both conditions, the activation of myofibroblast-like pancreatic stellate cells (PSCs) plays a predominant role in the formation of desmoplastic reaction through the synthesis of connective tissue and extracellular matrix, inducing local pancreatic fibrosis and an inflammatory response. Yet the signaling events involved in chronic pancreatitis and pancreatic cancer progression and metastasis remain poorly defined. Cadherin-11 (Cad-11, also known as OB cadherin or CDH11) is a cell-to-cell adhesion molecule implicated in many biological functions, including tissue morphogenesis and architecture, extracellular matrix-mediated tissue remodeling, cytoskeletal organization, epithelial-to-mesenchymal transition, and cellular migration. In this study, we show that, in human chronic pancreatitis and pancreatic cancer tissues, Cad-11 expression was significantly increased in PSCs and pancreatic cancer cells. In particular, an increased expression of Cad-11 can be detected on the plasma membrane of activated PSCs isolated from chronic pancreatitis tissues and in pancreatic cancer cells metastasized to the liver. Moreover, knockdown of Cad-11 in cancer cells reduced pancreatic cancer cell migration. Taken together, our data underline the potential role of Cad-11 in PSC activation and pancreatic cancer metastasis.

Few genes are associated with the capability of pancreatic ductal adenocarcinoma cells to grow in the liver of nude rats

Owing to aggressiveness and chemoresistance, pancreatic ductal adenocarcinoma (PDAC) is characterised by a poor prognosis. To address this disease-spe-cific dilemma we aimed to establish animal models, which can be used for identifying new specific tumor markers, as well as serving as tools for potential therapeutic approaches. From a panel of sixteen pancreatic cancer cell lines, two human (Suit2-007 and Suit2-013) and a rat (ASML) cell line were selected for their properties to grow in the liver of male RNU rats and mimic liver metastasis of PDAC. For better monitoring of metastatic tumor growth in vivo, all three pancreatic cancer cell lines were stably transfected with eGFP and luciferase marker genes. In addition, the mRNA expression profile of 13 human PDAC cell lines was analyzed by BeadChip array analysis. Only 33 genes and 5 signaling pathways were identified as significantly associated with the ability of the cell lines to grow initially and/or consistently in rat liver. Only a minority of these genes (osteopontin, matrix metalloproteinase-1 and insulin-like growth factor 1) has been intensively studied and shown to be closely related to cancer progression. The function of the remaining 30 genes ranges from moderate to poorly investigated, and their function in cancer progression is still unclear. The ensuing three pancreatic cancer liver metastasis models vary in their aggressiveness and macroscopic growth. They will be used for preclinical evaluation of new therapeutic approaches aiming at the genes identified.

Genome profiling of pancreatic adenocarcinoma

Pancreatic adenocarcinoma is one of the most aggressive human cancers. It displays many different chromosomal abnormalities and mutations. By using 244 K high-resolution array-comparative genomic hybridization (aCGH) we studied the genome alterations of 39 fine-needle aspirations from pancreatic adenocarcinoma and eight human adenocarcinoma pancreatic cell lines. Using both visual inspection and GISTIC analysis, recurrent losses were observed on 1p, 3p, 4p, 6, 8p, 9, 10, 11q, 15q, 17, 18, 19p, 20p, 21, and 22 and comprised several known or suspected tumor suppressor genes such as ARHGEF10, ARID1A, CDKN2A/B, FHIT, PTEN, RB1, RUNX1-3, SMAD4, STK11/LKB1, TP53, and TUSC3. Heterozygous deletion of the 1p35-p36 chromosomal region was identified in one-third of the tumors and three of the cell lines. This region, commonly deleted in human cancers, contains several tumor suppressor genes including ARID1A and RUNX3. We identified frequent genetic gains on chromosome arms 1q, 3q, 5p, 6p, 7q, 8q, 12q, 15q, 18q, 19q, and 20q. Amplifications were observed in 16 tumors. AKT2, CCND3, CDK4, FOXA2, GATA6, MDM2, MYC, and SMURF1 genes were gained or amplified. The most obvious amplification was located at 18q11.2 and targeted the GATA6 gene, which plays a predominant role in the initial specification of the pancreas and in pancreatic cell type differentiation. In conclusion, we have identified novel biomarkers and potential therapeutic targets in pancreatic adenocarcinoma.

p8 is a new target of gemcitabine in pancreatic cancer cells

Gemcitabine is the only available chemotherapeutic treatment of pancreatic cancers. It is, however, moderately effective, showing a tumor response rate of only 12%. The aim of this work was to identify new pathways involved in the resistance of pancreatic cancer cells to gemcitabine, in the hope of developing new adjuvant strategies to enhance its therapeutic efficacy. Comparison of gene expression patterns of five human pancreatic cancer cell lines showing different degrees of resistance to gemcitabine revealed specific overexpression of several genes in the most resistant. One of them encoded the antiapoptotic p8 protein. We found that (a) knocking down p8 expression in gemcitabine-resistant cells promoted cell death and increased caspase-3 activity; (b) forced overexpression of p8 in gemcitabine-sensitive cells increased their resistance to gemcitabine-induced apoptosis; and (c) gemcitabine down-regulated p8 mRNA expression. These results suggest that, in pancreatic cancer cells, a large part of gemcitabine-induced apoptosis results from the inhibition of the constitutive antiapoptotic activity of p8. Hence, targeting the p8-associated pathway could be a new adjuvant therapy improving the response of patients with pancreatic cancer to gemcitabine treatment.

Aberrant gata-3 expression in human pancreatic cancer

Gata-3 has been shown to specifically alter its expression patterns in different types of cancers. Recent evidence suggests that an interference of Gata-3 exists in the TGF-beta signaling pathway. To determine the role of Gata-3 in pancreatic cancer, pancreatic cancer samples were analyzed in comparison to normal pancreatic tissues. Furthermore, four different pancreatic cancer cell lines with different alterations of the TGF-beta pathway were studied. To evaluate if a potential relationship with TGF-beta signaling pathway exists, we correlated mRNA expression levels with the expression of TGF-betas, TGF-beta receptors, and Smad-3. Finally, we analyzed the influence of TGF-beta on Gata-3 expression in vitro. All pancreatic cancer samples demonstrated a marked overexpression of Gata-3 mRNA and protein. Immunohistochemical staining revealed strong and persistent cytoplasmic Gata-3 immunoreactivity in cancer cells. In an electrophoretic mobility shift assay, a disturbed nuclear translocation was confirmed. The expression of Gata-3 showed a significant correlation with the expression of TGF-betas, TGF-beta receptors, and Smad-3. TGF-beta responsive cell lines showed a downregulation of Gata-3 mRNA upon TGF-beta exposure, whereas in TGF-beta-unresponsive cell lines, Gata-3 mRNA expression persisted at high levels. Furthermore, strong specific upregulation of Gata-3 impaired nuclear translocation and its cooperative action with the TGF-beta pathway, suggesting that Gata-3 plays a central role in human pancreatic cancer.

Complications of pancreatic surgery

Pancreatic resection is the only treatment option that can lead to a meaningful prolonged survival in pancreatic cancer and, in some instances, perhaps a potential chance for cure. With the advent of organ and function preserving procedures, its use in the treatment of chronic pancreatitis and other less common benign diseases of the pancreas is increasing. Furthermore, over the past two decades, with technical advances and centralization of care, pancreatic surgery has evolved into a safe procedure with mortality rates of <5%. However, postoperative morbidity rates are still substantial. This article reviews the more common procedure-related complications, their prevention and their treatment.

Desmoplastic reaction influences pancreatic cancer growth behavior

Connective tissue growth factor (CTGF), which is regulated by transforming growth factor-ss (TGFss), has recently been implicated in the pathogenesis of fibrotic diseases and tumor stroma. Inasmuch as generation of desmoplastic tissue is characteristic for pancreatic cancer, it is not known whether it gives pancreatic cancer cells a growth advantage or is a reaction of the body to inhibit cancer cell progression. In the present study we analyzed the expression and localization of CTGF and evaluated whether it influences the prognosis of pancreas cancer. Tissue samples were obtained from 25 individuals (6 women, 19 men) undergoing pancreatic resection for pancreatic cancer. Tissue samples from 13 previously healthy organ donors (5 women, 8 men) served as controls. Expression of CTGF was studied by Northern blot analysis. In situ hybridization and immunohistochemistry localized the respective mRNA moieties and proteins in the tissue samples. Northern blot analysis revealed that pancreatic cancer tissue samples exhibited a 46-fold increase in CTGF mRNA expression ( p < 0.001) over that of normal controls. In vitro studies confirmed that pancreatic stellate cells are the major source of CTGF mRNA expression and revealed a large variance in basal and TGFss-induced CTGF expression in cultured pancreatic cancer cells. This could also be confirmed by in situ hybridization, indicating that CTGF mRNA signals were located principally in fibroblasts, with only weak signals in the cancer cells. High CTGF mRNA levels in the tissue samples correlated with better tumor differentiation ( p < 0.03). In addition, patients whose tumors exhibited high CTGF mRNA levels (> onefold increase above normal controls) lived significantly longer than those whose tumors expressed low CTGF mRNA levels (none to onefold) ( p < 0.04 multivariate analysis). Our present data indicate that CTGF, as a downstream mediator of TGFss, is overexpressed in connective tissue cells and to a lesser extent in pancreatic cancer cells. Because patients with high CTGF mRNA expression levels have a better prognosis, our findings indicate that the desmoplastic reaction provides a growth disadvantage for pancreatic cancer cells.

Effects of STI571 (gleevec) on pancreatic cancer cell growth

BACKGROUND

Pancreatic cancer is an aggressive malignancy characterized by low responsiveness to chemotherapy and radiotherapy. This resistance is partly due to the overexpression of several tyrosine kinase receptors and their ligands. STI571 has specific activity in inhibiting c-kit, PDGF and Abl receptor tyrosine kinases and has proven successful in the treatment of CML and GIST patients. Here, we investigated the potential role of STI571 in pancreatic cancer.

RESULTS

The GI50 of STI571 as well as the effects of STI571 on growth factor actions in pancreatic cell lines were analyzed using the MTT assay. FACS analysis using Annexin and PI staining was performed to study cell cycle, apoptosis, and cell death. Western blot analysis was carried out to investigate MAP kinase and receptor tyrosine kinase phosphorylation. STI571 inhibited cell proliferation in pancreatic cancer cell lines with GI50 concentrations ranging from 17 to 31.5 microM. EGF, IGF-1, and FGF-2 but not PDGF exerted growth stimulatory effects in pancreatic cancer cell lines. STI571 only partly blocked these effects on cell growth, and did not abrogate growth factor-induced receptor and MAPK phosphorylation.

CONCLUSION

Our data demonstrate that STI571 inhibits pancreatic cancer cell growth with high GI50 concentrations through tyrosine-kinase receptor independent pathways. The clinical application of STI571 in pancreatic cancer is therefore rather doubtful.

Apoptosis: targets in pancreatic cancer

Pancreatic adenocarcinoma is characterized by poor prognosis, because of late diagnosis and lack of response to chemo- and/or radiation therapies. Resistance to apoptosis mainly causes this insensitivity to conventional therapies. Apoptosis or programmed cell death is a central regulator of tissue homeostasis. Certain genetic disturbances of apoptotic signaling pathways have been found in carcinomas leading to tumor development and progression. In the past few years, the knowledge about the complex pathways of apoptosis has strongly increased and new therapeutic approaches based on this knowledge are being developed. This review will focus on the role of apoptotic proteins contributing to pancreatic cancer development and progression and will demonstrate possible targets to influence this deadly disease.

Increased arylhydrocarbon receptor expression offers a potential therapeutic target for pancreatic cancer

The arylhydrocarbon receptor (AhR) was initially identified as a member of the adaptive metabolic and toxic response pathway to polycyclic aromatic hydrocarbons and to halogenated dibenzo-p-dioxins and dibenzofurans. In the present study, we sought to determine the functional significance of the AhR pathway in pancreatic carcinogenesis. AhR expression was analysed by Northern blotting. The exact site of AhR expression was analysed by in situ hybridization and immunohistochemistry. The effects of TCDD and four selective AhR agonists on pancreatic cancer cell lines were investigated by growth assays, apoptosis assays, and induction of the cyclin-dependent kinase inhibitor p21. There was strong AhR mRNA expression in 14 out of 15 pancreatic cancer samples, weak expression in chronic pancreatitis tissues, and faint expression in all normal pancreata. In pancreatic cancer tissues, AhR mRNA and protein expression were localized in the cytoplasm of pancreatic cancer cells. TCDD and the four AhR agonists inhibited pancreatic cancer cell growth in a dose-dependent manner, and decreased anchorage-independent cell growth. DAPI staining did not reveal nuclear fragmentation and CYP1A1 and was not induced by TCDD and AhR agonists. In contrast, TCDD and AhR agonists induced the expression of the cyclin-dependent kinase inhibitor p21. In conclusion, the relatively non-toxic AhR agonists caused growth inhibition in pancreatic cancer cells with high AhR expression levels via cell cycle arrest. In addition, almost all human pancreatic cancer tissues expressed this receptor at high levels, suggesting that these or related compounds may play a role in the therapy of pancreatic cancer in the future.

Pancreatic cancer: factors regulating tumor development, maintenance and metastasis

Pancreatic cancer has one of the poorest prognoses of all gastrointestinal malignancies. Today, it is the fourth or fifth leading cause of cancer-related deaths in Western industrialized countries, and the incidence has been increasing throughout the past decades. Insensitivity to growth-inhibitory and apoptotic signals as well as self-sufficiency of growth-promoting factors are hallmarks of the pathogenesis of this malignancy. In pancreatic cancer, a variety of growth factors and their receptors are expressed at increased levels. For example, the concomitant presence of the epidermal growth factor (EGF) receptor and its ligand EGF is associated with enhanced tumor aggressiveness and shorter survival following tumor resection. Furthermore, a number of other growth factors and their receptors, such as nerve growth factor and its receptor, are overexpressed in pancreatic cancer and contribute to its malignant phenotype. Besides factors which directly promote cell proliferation, a variety of other factors such as galectins are upregulated, which influences the tumor environment and the invasiveness of pancreatic cancer cells. In addition, tumor suppressor genes such as KAI1 are expressed at reduced levels, thereby enhancing the ability of pancreatic cells to form metastases. A complex disturbance of factors is present in pancreatic cancer, resulting in a distinct growth advantage which clinically results in rapid tumor progression and poor patient survival.

Adhesion molecules in human pancreatic cancer

BACKGROUND AND OBJECTIVES

Adhesion molecules are cell surface glycoproteins that are important in cell-to-cell and cell-to-extracellular matrix interactions. In the present study, we analyzed the adhesion molecules ICAM-1 (intercellular adhesion molecule-1), VCAM-1 (vascular cell adhesion molecule-1), and ELAM-1 (endothelial leukocyte adhesion molecule-1) in human pancreatic cancer.

METHODS

ICAM-1, VCAM-1, and ELAM-1 were analyzed in 20 pancreatic cancer specimens and 20 normal pancreatic tissues. mRNA expression encoding ICAM-, VCAM-1, and ELAM-1 was assessed with Northern blot analysis. The distribution and localization of ICAM-1, VCAM-1, and ELAM-1 was determined in the pancreatic specimens by immunohistochemistry.

RESULTS

Northern blot analysis revealed a 5.4-fold increase of ICAM-1 (P<0.01) and a 3.7-fold increase in VCAM-1 (P<0.01) mRNA expression in cancer samples in comparison with normal controls. In contrast, ELAM-1 mRNA levels did not show significant differences between the cancer and the normal tissues. Immunohistochemical analysis of cancer tissues showed strong immunostaining for ICAM-1 and VCAM-1, and faint immunostaining for ELAM-1 in the pancreatic cancer cells. Fibrotic or noncancerous pancreatic tissue adjacent to the cancer mass was devoid of any immunoreactivity for ICAM-1, ELAM-1, and VCAM-1. In contrast, the normal pancreas exhibited no immunoreactivity of ICAM-1, ELAM-1, and VCAM-1.

CONCLUSIONS

Enhanced expression of ICAM-1 and VCAM-1 in human pancreatic cancers suggests a role in tumor pathogenesis. The increase of these adhesion molecules might influence the detachment of cancer cells in the primary tumor, might contribute to cancer cell migration and the spread of cancer cells to distant organs, or both.

Influences of the lysosomal associated membrane proteins (Lamp-1, Lamp-2) and Mac-2 binding protein (Mac-2-BP) on the prognosis of pancreatic carcinoma

BACKGROUND

Lamps and Mac-2-BP are ligands of galectin-3, and they were suggested to influence tumor proliferation and metastasis formation. The authors studied the expression of Lamp-1, Lamp-2, and Mac-2-BP in pancreatic carcinoma and evaluated their influence on patient prognosis.

METHODS

Northern blot analysis, in situ hybridization, and immunohistochemistry were performed in 12 normal and 28 pancreatic carcinoma tissue samples and in pancreatic carcinoma cell lines. The molecular findings in the tumor samples were correlated with the prognosis and histopathologic tumor characteristics. In addition, in Lamp-1 transfected CAPAN-1 pancreatic carcinoma cells, cell proliferation was analyzed.

RESULTS

Lamp-1, Lamp-2, and Mac-2-BP were overexpressed in 61% (1.6-fold increase, not significant), 71% (3.0-fold increase, P < 0.01), and 93% (5.6-fold increase, P < 0.01) of the pancreatic carcinoma samples. Lamp-1 and Lamp-2 immunoreactivity was present at the luminal side of the ductal carcinoma cells whereas Mac-2-BP immunoreactivity was diffusely spread over the whole cytoplasm and the nucleolus of ductal carcinoma cells. Correlation of the molecular data with clinical patient parameters revealed that patients whose tumors exhibited high Lamp-1 mRNA expression lived significantly longer (median, 17 months) after tumor resection than patients whose tumors exhibited low to moderate Lamp-1 mRNA levels (median, 8 months; P < 0.02). No relation between Lamp-2 and Mac-2-BP mRNA expression and any of the histopathologic parameters was found. Lamp-1 transfected CAPAN-1 cells showed decreased cell growth compared with the nontransfected cells.

CONCLUSIONS

Lamp-1 might influence local tumor progression rather than the formation of tumor metastasis in pancreatic carcinoma, whereas Mac-2-BP and Lamp-2 seem to have little influence on these parameters in pancreatic carcinoma.

Bcl-x(L) antisense oligonucleotides induce apoptosis and increase sensitivity of pancreatic cancer cells to gemcitabine

Pancreatic cancer is one of the leading causes of cancer-related death in Western countries. Bcl-x(L) is an anti-apoptotic factor of the Bcl-2 family, which is overexpressed in pancreatic cancer and its presence correlates with shorter patient survival. In this study, sequence-specific antisense oligonucleotides targeting the coding region of Bcl-x(L) were designed to examine whether apoptosis could be induced and chemosensitivity could be increased in pancreatic cancer cells. Five pancreatic cancer cell lines, Panc-1, MIA-PaCa-2, Capan-1, ASPC-1 and T3M4, were treated with Bcl-x(L) sense or antisense oligonucleotides and gemcitabine and the cell viability was examined by the SRB method. Apoptosis was determined using DAPI staining. In all examined pancreatic cancer cells, Bcl-x(L) expression was reduced after transfection of the antisense oligonucleotides. Cell death analysis using DAPI staining revealed that antisense, but not sense oligonucleotides caused apoptotic cell death. Furthermore, Bcl-x(L) antisense oligonucleotides enhanced the cytotoxic effects of gemcitabine in pancreatic cancer cells. Our results indicate that Bcl-x(L) antisense oligonucleotides effectively inhibited pancreatic cancer cell growth and caused apoptosis by reducing Bcl-x(L) protein levels. Bcl-x(L) antisense oligonucleotides also increased the chemosensitivity of pancreatic cancer cells, suggesting that Bcl-x(L) antisense therapy might be a potential future approach in this disease.

Growth factors and their receptors in pancreatic cancer

Pancreatic cancer has an incidence of approximately 8 to 10 cases per 100,000 citizens in Western industrialized countries, and the incidence has been increasing throughout the last decades. Insensitivity to antigrowth and apoptotic signals as well as self-sufficiency in growth signals are hallmarks of malignant growth. Pancreatic cancers often exhibit alterations in growth inhibitory pathways such as Smad4 mutations and Smad6 and Smad7 overexpression, and evade apoptosis through p53 mutations and aberrant expression of apoptosis regulating genes. In addition, in pancreatic cancer a variety of growth factors are expressed at increased levels. For example, the concomitant presence of the EGF-receptor and its ligands EGF, TGF-alpha, and/or amphiregulin is associated with enhanced tumor aggressiveness and shorter survival periods following tumor resection. Furthermore, a number of other growth factors and their receptors, such as fibroblast growth factors, nerve growth factor, platelet-derived growth factors, and insulin-like growth factors and their respective receptors are expressed at increased levels in pancreatic cancer and are thought to contribute to its malignant phenotype. Taken together, the disturbance of growth inhibitory and apoptotic pathways and the abundance of growth promoting factors give pancreatic cancer cells a distinct growth advantage which clinically results in rapid tumor progression and poor survival prognosis.

Expression of the multidrug-resistance 1 (MDR1) gene and prognosis in human pancreatic cancer

Multidrug-resistance 1 (MDR1) encodes a 170 kDa transmembrane glycoprotein (P-glycoprotein), which acts as a drug-efflux pump. In the present study, we analyzed the expression of MDR1/P-glycoprotein in human pancreatic cancer and correlated the results with clinical parameters. Pancreatic cancer tissue samples were obtained from 67 patients (30 female, 37 male) who underwent surgery. Normal pancreatic tissues obtained from 15 previously healthy organ donors (4 female, 11 male) served as controls. MDR1 mRNA levels were analyzed by Northern blotting, and the exact site of MDR1 mRNA expression was determined by in situ hybridization and immunohistochemistry. Northern blot analysis indicated that in comparison with the normal pancreas, MDR1 mRNA levels were only increased 1.4-fold (p = 0.03) in the pancreatic cancer samples. However, there was a 2.9-fold (p < 0.01) increase in MDR1 mRNA levels when only the samples that exhibited increased expression (38%) were analyzed. In situ hybridization and immunohistochemical analysis showed that MDR1 was highly expressed in the cancer cells of these samples. Statistical analysis revealed that patients with high MDR1/P-glycoprotein expression had a shorter postoperative survival time compared with patients with weak to moderate expression of MDR1. On the basis of in situ hybridization, survival in the intense group was 11.6 (n = 12) versus 14.2 months (n = 42) in the mild to moderate group. On the basis of immunohistochemistry, survival in the intense group was 7.5 months (n = 10) versus 14.1 months (n = 40) in the mild to moderate group. Surprisingly, survival of patients with high expression of MDR1/P-glycoprotein was not significantly different from that of patients without detectable MDR1/P-glycoprotein expression. These findings suggest that both strong expression of MDR1/P-glycoprotein and lack of expression seem to influence tumor growth via known and yet unknown mechanisms.

Enhanced expression of Silencer of death domains (SODD/BAG-4) in pancreatic cancer

Pancreatic cancers are resistant to TNF-alpha-mediated apoptosis. Silencer of death domains (SODD) binds to TNF-alpha receptor TNFR-1, and prevents spontaneous self-association of death domains and inappropriate receptor signaling. In addition, overexpression of SODD suppresses TNF-alpha-induced cell death. In this report, we demonstrate increased SODD mRNA levels in pancreatic cancer (n = 30) in comparison to normal control tissues (n = 20, P < 0.01). In situ hybridization analysis revealed SODD expression predominantly in the cancer cells within the pancreatic tumor mass. In contrast, SODD mRNA levels were not different (P > 0.05) in four other gastrointestinal cancers (liver, esophagus, stomach, colon) compared with the corresponding normal tissues. These findings indicate that in contrast to other gastrointestinal malignancies, in pancreatic cancer SODD might block TNF-alpha-mediated apoptosis which may influence the growth of pancreatic cancer cells.

The significance of somatostatin analogues in the antiproliferative treatment of carcinomas

Somatostatin is a cyclic tetradecapeptide hormone. It was initially isolated from bovine hypothalami. Somatostatin inhibits endocrine and exocrine secretion, as well as tumor cell growth, by binding to specific cell-surface receptors. Its potent inhibitory activity is limited, however, by its rapid enzymatic degradation and the consequently short plasma half-life. Octreotide is a short somatostatin analogue with increased duration of action compared with somatostatin. Preclinical studies have focused on the anticancer effects of octreotide and the related somatostatin analogues. In vitro, at nanomolar concentrations, these analogues inhibit the growth of tumor cells that express high-affinity somatostatin receptors. Accordingly, such analogues potently inhibit the growth of somatostatin receptor-positive tumors in various rodent models. The range of cancers susceptible to octreotide and related somatostatin analogues includes mammary, pancreatic, gastric, colorectal, prostate, thyroid, and lung carcinomas. Moreover, an indirect antiproliferative effect of somatostatin analogues is achievable in somatostatin receptor-negative tumors whose growth is driven by factors (e.g., gastrin, insulin-like growth factor-1) that become down-regulated by somatostatin. The clinical effect of somatostatin analogues in terms of tumor response in cancer patients is a subject of controversy, however. Most responses have been seen in patients with pancreatic cancers.

Growth factors and cytokines in pancreatic carcinogenesis

Pancreatic cancer is a deadly disease challenging basic and clinical researchers alike in characterizing its pathobiology and finding better treatment options. A number of molecular alterations including gene mutations such as k-ras, p53, and Smad4 and aberrant expression of a variety of genes have been identified in recent years. This review focuses on two families of growth factors and growth factor receptors which are representative for the molecular alterations observed in pancreatic cancer: the transforming growth factor-beta superfamily of serine-threonine kinase receptors and their ligands, which usually act as negative growth regulators, and the epidermal growth factor receptor family and their ligands, which have the potential to act as growth promoters in pancreatic cancer. In addition, we will discuss the role of the cytokines TNF-alpha, IFN-gamma, and IL-6 and its effects on pancreatic cancer cell proliferation in vitro and in vivo. Pancreatic cancer cell biology consists of complex interactions of various factors, and a better understanding of the molecular pathogenesis of this disorder might lead to better treatment strategies in the near future.

Bone morphogenetic protein 2 exerts diverse effects on cell growth in vitro and is expressed in human pancreatic cancer in vivo

BACKGROUND & AIMS

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor beta superfamily of signaling molecules. We characterized the expression of BMP-2 and its receptors in human pancreatic tissues and pancreatic cancer cell lines and examined the effects of BMP-2 on mitogenesis.

METHODS

Expression of BMP-2 and its receptors was determined by Northern blot analysis using specific complementary DNA probes. Distribution of BMP-2 in pancreatic cancers was examined by immunohistochemistry and in situ hybridization. Effects of BMP-2 on mitogenesis were assessed by monitoring cell proliferation and activation of mitogen-activated protein kinase (MAPK).

RESULTS

Compared with the normal pancreas, pancreatic cancers showed a 12.5-fold (P < 0.01), 2-fold (P < 0.01), and 8-fold (P < 0.01) increase of BMP-2, BMP receptor (R)-IA, and BMPR-II messenger RNA levels, respectively. By immunohistochemistry and in situ hybridization, BMP-2 was expressed in the cancer cells within the tumor mass. There was a significant correlation between the presence of BMP-2 immunostaining in the tumors and shorter postoperative survival. Pancreatic cancer cell lines expressed variable levels of messenger RNA encoding BMP-2 and its receptors. BMP-2 stimulated the growth of two pancreatic cancer cell lines (ASPC-1 and CAPAN-1). This mitogenic effect was associated with MAPK activation and blocked by the MAPK inhibitor PD98059 in CAPAN-1 but not in ASPC-1 cells. In both cell lines, expression of wild-type Smad4 abolished the BMP-2-mediated growth stimulation. BMP-2 inhibited the growth of COLO-357 cells, an effect that was blocked by expressing a dominant negative Smad4. BMP-2 had no effect in three cell lines that underexpressed either the BMP receptors or Smad1.

CONCLUSIONS

These findings indicate that BMP-2 has the capacity to act as a mitogen when Smad4 is mutated and suggest that it might play a role in the pathobiology of human pancreatic cancer.

Luteinizing hormone-releasing hormone analogs: their impact on the control of tumorigenesis

The development of the luteinizing hormone-releasing hormone (LH-RH) agonists and antagonists and the principles of their clinical use were reviewed. In the 28 years that have elapsed since the elucidation of the structure of LH-RH, various applications in gynecology, reproductive medicine, and oncology have been established for LH-RH agonists and antagonists. These clinical applications are based on inhibition of the pituitary and the gonads. The advantage of the LH-RH antagonists is due to the fact that they inhibit the secretion of gonadotropins and sex steroids immediately after the first injection and thus achieve rapid therapeutic effects in contrast to the agonists, which require repeated administration. LH-RH antagonists should find applications in the treatment of benign gynecologic disorders and benign prostatic hypertrophy and in assisted reproduction programs. The primary treatment of advanced androgen-dependent prostate cancer is presently based on the use of depot preparations of LH-RH agonists, but antagonists like Cetrorelix already have been tried successfully. Antagonists of LH-RH might be more efficacious than agonists in treatment of patients with breast cancer as well as ovarian and endometrial cancer. Recently, practical cytotoxic analogs of LH-RH that can be targeted to LH-RH receptors on tumors have been synthesized and successfully tested in experimental cancer models. Targeted cytotoxic LH-RH analogs show a great promise for therapy of prostate, breast, and ovarian cancers.

Moderate activation of the apoptosis inhibitor bcl-xL worsens the prognosis in pancreatic cancer

OBJECTIVE

To analyze the expression of the antiapoptotic gene bcl-xL in human pancreatic cancer and to correlate the results with clinical patient parameters.

SUMMARY BACKGROUND DATA

Bcl-xL belongs to the bcl-2-related gene family and acts as a broad antiapoptotic factor to extend both normal and tumor cell survival. Recent findings indicate that tumor cell death induced by chemotherapy and radiotherapy is mediated by the activation of apoptosis. The fact that pancreatic cancer has an extremely malignant potential and that it is resistant to most anticancer treatment modalities suggests that mechanisms are activated that increase the viability of pancreatic cancer cells.

METHODS

Seventy-four pancreatic cancer tissue samples were obtained from 32 female and 42 male patients undergoing surgery for exocrine pancreatic cancer. Normal human pancreatic tissue samples were available from 11 organ donors and 4 patients without pancreatic disease. The levels of bcl-xL mRNA expression were analyzed by Northern blot analysis. The exact site of bcl-xL mRNA transcription was determined by nonradioactive in situ hybridization. In addition, immunohistochemistry using specific polyclonal antibodies was used to localize the protein.

RESULTS

Northern blot analysis indicated that, in comparison with the normal pancreas, bcl-xL mRNA was markedly overexpressed in 54% of the pancreatic cancer samples. Densitometric analysis revealed that pancreatic adenocarcinomas exhibited a mean 3.4-fold increase (p < 0.01) in bcl-xL mRNA levels in comparison with normal controls. With in situ hybridization, bcl-xL mRNA was found to be highly expressed in the cancer cells of tumor samples that exhibited increased mRNA expression by Northern blot analysis. Immunohistochemical analysis revealed bcl-x immunostaining in 88% of the cancer samples. Correlation of the molecular data with clinical patient parameters revealed that patients whose tumors exhibited no, faint, or weak bcl-xL expression lived significantly longer after tumor resection (median 12 months) than patients whose tumors exhibited moderate bcl-xL mRNA expression (median 5 months) (p < 0.05). However, 5 patients whose tumors exhibited intense bcl-xL mRNA expression tended to live longer (median 14 months).

CONCLUSION

Enhanced expression of the antiapoptotic gene bcl-xL in pancreatic cancer and its association with shorter patient survival suggests that this factor may enhance the viability of pancreatic cancer cells in vivo. Inhibition of apoptotic pathways might be one of the reasons why pancreatic cancer shows only limited sensitivity to anticancer treatment.

Rational use of agonists and antagonists of luteinizing hormone-releasing hormone (LH-RH) in the treatment of hormone-sensitive neoplasms and gynaecologic conditions

Analogues of luteinizing hormone-releasing hormone (LH-RH) have made possible new approaches to the treatment of some hormone-dependent cancers and diseases and conditions which result from inappropriate sex hormone levels. In the fields of both gynaecology and oncology, the development of sustained delivery depot systems has played a key role in the clinical use of LH-RH agonists and will be also essential for the LH-RH antagonists. Clinical results show that therapy with agonists of LH-RH is the preferred method of treatment for men with advanced prostate cancer. For prostate cancer and other indications, the new LH-RH antagonists such as Cetrorelix may offer an advantage based on the fact that they inhibit LH, FSH and sex-steroid secretion from the start of the administration and thus reduce the time of the onset of therapeutic effects. The use of antagonists would avoid the temporary clinical "flare-up" of the disease which can occur with the agonists in men with prostate cancer. The rapid shrinkage of the prostate and improvement in urinary symptoms obtained with Cetrorelix in men with benign prostatic hyperplasia (BHP) suggests that LH-RH antagonists offer a therapeutic alternative in patients who are considered poor surgical risks. Various experimental and clinical studies suggest that analogues of LH-RH might be useful for treatment of premenopausal women with oestrogen-dependent breast cancer. LH-RH antagonists such as Cetrorelix could be also considered for hormonal therapy of epithelial ovarian cancer which responds only marginally to the agonists, and for treatment of endometrial cancer. Many investigators have reported beneficial effects of LH-RH agonists in the treatment of patients with leiomyomas. LH-RH antagonists also appear to be promising for therapy of uterine leiomyomas, and in addition might be useful for treatment of endometriosis and polycystic ovarian disease (PCOD). LH-RH agonists have been employed in in vitro fertilization and embryo transfer (IVF-ET) programs to prevent a premature rise in LH and various results suggest that the use of antagonist Cetrorelix in assisted reproduction procedures, could be even more advantageous. For most of these indications, the use of sustained release depot preparations will be required.

Adjuvant therapy of pancreatic cancer using monoclonal antibodies and immune response modifiers

Pancreatic cancer is a devastating disease with poor survival. At present, no effective adjuvant or palliative therapies are available. Unresponsiveness to chemotherapy, radiotherapy, and antihormonal treatment is one of the reasons that pancreatic cancer patients have an overall median survival time of 4-6 mo. This article summarizes clinical trials on immunotherapy of pancreatic cancer using the murine monoclonal antibodies (MAbs) 17-1A and BW 494. In addition, the use of MAb treatment in combination with immune response modifiers is discussed. In four clinical trials, MAb 17-1A was given by iv infusion to 100 patients with pancreatic cancer. In 30 of the these patents, antibody treatment was accompanied by gamma-interferon, also given intravenously. Complete response, partial response, and stable disease were reported in 1,5, and 23 patients, respectively. Passive immunotherapy using the MAb BW 494 was carried out in 148 pancreatic cancer patients in two phase I and two phase II trials. In 1 out of 75 patients a partial response and in 25 out of 74 patients stable disease were reported. However, in a controlled randomized trial enrolling 61 patients following Whipple resection, comparable survival times in patients with and without MAb BW 494 treatment led to the termination of further clinical trials with this antibody. New clinical studies using humanized MAbs in combination with immune response modifiers should be initiated to further evaluate immunotherapy as a treatment option in pancreatic cancer.

Octreotide combined with goserelin in the therapy of advanced pancreatic cancer--results of a pilot study and review of the literature

The two hormone analogues octreotide and goserelin have been shown to decelerate growth of human pancreatic cancer in vitro and in vivo. The objective of this pilot study was to investigate the efficacy and toxicity of the combination of these two agents in patients with advanced pancreatic cancer. Octreotide was injected subcutaneously in dosages increasing weekly, starting with 50 micrograms twice daily, until the level of maintenance therapy of 500 micrograms three times a day was reached. In addition, 3.8 mg goserelin acetate was administered subcutaneously at monthly intervals. A median of 7 cycles (range 1-27 cycles) were applied; 13 out of 14 patients entered into the study were evaluable for response and all 14 were evaluated for toxicity. In one patient with initially non-resectable pancreatic cancer, systemic therapy yielded a partial remission lasting 9 months. The degree of tumour regression then allowed a consecutive macroscopic radical tumour resection followed by an additional 6 months of no evidence of disease while the same drug combination was continued. In an additional 9 patients, no change of disease was observed, in some cases for a remarkably long time (up to 27 months). Nevertheless, the objective response rate of 7% (95% confidence interval 0 +/- 21%) was low. In 5 patients a clear improvement in their performance status was seen soon after the start of therapy; 3 patients showed progression of the disease at first evaluation or earlier and 1 patient was not evaluable at the time of study assessment. According to the product-limit method of Kaplan and Meier, the time to progression was 3.0 +/- 1.8 months [median +/- asymptotic standard error (ASE)] and overall survival was 6.0 +/- 1.5 months (median +/- ASE). Toxicity was rare and only of mild to moderate degree. Overall, the regimen under investigation did not meet the criteria for sufficient antitumoural effectiveness. Nevertheless, this study reinforces the concept that pancreatic cancer is principally responsive to endocrine therapy and therefore the further investigation of hormonal manipulation seems worth while in the future.

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.

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.