Cholecystokinin receptor antagonist, loxiglumide, inhibits invasiveness of human pancreatic cancer cell lines

The protective effects of in vitro cultivated calculus bovis on the cerebral and myocardial cells in hypoxic mice

The protective effects of in vitro cultivated calculus bovis (ICCB) on the cerebral and myocardial cells in hypoxic mice and the mechanism were examined. In one group, mice were intragastrically (i.g.) given ICCB for 15 days and then they were subjected to acute cerebral ischemia by decapitation, and then the panting time was recorded. In the other group, 12 min after exposure to hypoxia, mice was administered the ICCB i.g. for 5 days, and then the blood serum and tissues of brain, heart, liver were harvested and examined for SOD, GSH-px and T-AOC activity and content of MDA. The tissues of brain and heart were observed electron-microscopically for ultrastructural changes. The corpus striatum and hippocampus of brain were collected and examined for content of dopamine (DA) and norepinephrine (NE). The ultrastructural examination showed that the pathological change in brain and heart in the ICCB group was very slight, while abnormal changes in the control group were obviously more serious. ICCB significantly prolonged the panting time of the hypoxic mice (P<0.001), increased the activity of SOD, GSH-px, T-AOC in serum and tissues of brain, liver, heart and elevated the content of DA and NE. ICCB also pronouncedly reduced content of MDA in serum and tissues of brain, heart and liver. Significant differences in these parameters were noted between ICCB group and controls. It is concluded that ICCB can exert protective effect on the cells of brain and myocardium by enhancing the tolerance of the tissues to hypoxia and the body's ability to remove free radicals and regulating the neurotransmitters.

CUB domain-containing protein 1, a prognostic factor for human pancreatic cancers, promotes cell migration and extracellular matrix degradation

CUB domain-containing protein 1 (CDCP1) is a membrane protein that is highly expressed in several solid cancers. We reported previously that CDCP1 regulates anoikis resistance as well as cancer cell migration and invasion, although the underlying mechanisms have not been elucidated. In this study, we found that expression of CDCP1 in pancreatic cancer tissue was significantly correlated with overall survival and that CDCP1 expression in pancreatic cancer cell lines was relatively high among solid tumor cell lines. Reduction of CDCP1 expression in these cells suppressed extracellular matrix (ECM) degradation by inhibiting matrix metalloproteinase-9 secretion. Using the Y734F mutant of CDCP1, which lacks the tyrosine phosphorylation site, we showed that CDCP1 regulates cell migration, invasion, and ECM degradation in a tyrosine phosphorylation-dependent manner and that these CDCP1-associated characteristics were inhibited by blocking the association of CDCP1 and protein kinase Cdelta (PKCdelta). CDCP1 modulates the enzymatic activity of PKCdelta through the tyrosine phosphorylation of PKCdelta by recruiting PKCdelta to Src family kinases. Cortactin, which was detected as a CDCP1-dependent binding partner of PKCdelta, played a significant role in migration and invasion but not in ECM degradation of pancreatic cells. These results suggest that CDCP1 expression might play a crucial role in poor outcome of pancreatic cancer through promotion of invasion and metastasis and that molecules blocking the expression, phosphorylation, or the PKCdelta-binding site of CDCP1 are potential therapeutic candidates.

Construction of porcine CCK pDNA and its expression in COS-7 cells

CCK correlates with the generation and progression of pancreatic cancer. The research aims to construct eukaryotic expression plasmid pIRES2-EGFP/CCK (CCK pDNA) and transiently express it in COS-7 cells. Total RNA was extracted from porcine intestinal mucosa. RT-PCR was used to amplify the aimed segments CCKcDNA which was then digested with EcoR1 and BamH1 and inserted into a eukaryotic expression plasmid pIRES2-EGFP to construct CCK pDNA. The constructed plasmid was transfected into COS-7 cells by lepofectamin 2000-mediated transfer method. The expression of CCK in transfected COS-7 cells was detected 24, 48 and 72 h post-transfection with fluorescence microscopy and the expression level of CCK mRNA in transfected COS-7 cells was assayed by using RT-PCR. The results showed CCK pDNA was successfully constructed and expressed transiently in COS-7 cells. Green fluorescent protein could be detected in the COS-7 cells transfected with porcine CCK pDNA 24 h post-transfection. At 48th h post-transfection, the number of positive cells was increased significantly and much brighter green fluorescence could be detected. And 72 h post-transfection, the green fluorescence of positive cells became even stronger, while no green fluorescence was detected in the control group. The expression of CCK mRNA in the cells was detectable by using RT-PCR. In COS-7 cells transfected with CCK pDNA a high level of porcine CCK mRNA was detected while no expression of porcine CCKmRNA was found in the cells transfected with null plasmid. It was concluded CCK pDNA was expressed successfully in COS-7 cells, which lays a foundation for further research on the relationship between CCK and tumor.

The role of glial cell line-derived neurotrophic factor (GDNF) and integrins for invasion and metastasis in human pancreatic cancer cells

BACKGROUND AND OBJECTIVES

It is generally accepted that the malignancy of pancreatic cancer is dependent upon the extent of invasion as well as metastasis. However, the factors and mechanisms are incompletely understood. We investigated whether glial cell lined-derived neurotrophic factor (GDNF) enhances the invasive and adhesive behaviors of pancreatic cancer cells by altering of the expression of integrins.

METHODS

The expression of the GDNF receptor in pancreatic cancer cell lines (SW1990 and Capan-2) was confirmed by RT-PCR. Then we determined the expression of integrin subunits and the alteration of their expression by GDNF using flow-cytometric analysis and a cellular enzyme-linked immunosorbent assay (CELISA). Adhesion and invasion assay were performed to investigate whether increased integrin expression affected the interaction between cancer cells and ECM proteins.

RESULTS

The GDNF receptor subunits were expressed in pancreatic cancer cells. GDNF enhanced the expression of some of the integrin subunits and increased their adhesive and invasive abilities. The enhanced expression and associated increase in adhesive and invasive abilities were inhibited by blocking the GDNF receptor or the integrin beta1 subunit.

CONCLUSION

The enhancement of integrin expression by GDNF signaling through the GDNF receptor strongly influences invasion and adhesion to ECM proteins by pancreatic cancer cells.

Gastrins, cholecystokinins and gastrointestinal cancer

The gastrointestinal peptide hormones gastrin and cholecystokinin (CCK) are well known for their ability to stimulate gastric acid secretion and pancreatic enzyme secretion, respectively. The suggestion that gastrin and CCK might also promote the development of cancers of the gastrointestinal tract has been controversial, but an increasing body of evidence now supports the view that the amidated and non-amidated forms of gastrin act as growth factors via different receptors in different regions of the gut. For example, animal experiments indicate that amidated gastrins are involved in cellular differentiation and repair in the gastric mucosa, and synergize with Helicobacter pylori infection in the development of gastric carcinoma. In contrast, non-amidated gastrins stimulate colonic mucosal growth, accelerate the early steps in colorectal carcinoma formation, and are elevated in the tumour and circulation of patients with colorectal cancer. Although human pancreatic carcinomas express CCK-1 and CCK-2 receptors, the role of gastrins and CCK in pancreatic carcinogenesis is yet to be established. Further investigation of the possible role of the CCK-2 receptor in gastric and pancreatic neoplasia, and of the hypothesis that gastrin precursors act as autocrine growth factors in colorectal carcinoma, is warranted. However, therapies aimed at the gastrins must be targeted to the relevant gastrin/gastrin receptor combination.

Alteration of integrin expression by glial cell line-derived neurotrophic factor (GDNF) in human pancreatic cancer cells

INTRODUCTION

Pancreatic cancer cells express a number of functionally active integrins that are related to their adhesive and invasive abilities.

AIMS

To determine whether glial cell line-derived neurotrophic factor (GDNF) influences the expression of integrins in pancreatic cancer cell lines and to elucidate the mechanisms of adhesion and invasion to extracellular matrix (ECM) proteins.

METHODOLOGY

The expression of integrin subunits and the alteration of their expression by GDNF were examined by flow-cytometric analysis and cellular enzyme-linked immunosorbent assay in pancreatic cancer cell lines (MIA PaCa-2 and BxPC-3). Assays of adhesion and invasion of cancer cells to ECM proteins were conducted to investigate whether increased integrin expression affects the interaction between cancer cells and putative integrin ECM ligands.

RESULTS

Expression of some of the integrin subunits in pancreatic cancer cells was enhanced by GDNF. The enhancement and associated increase in adhesive and invasive ability by GDNF were inhibited by blocking the GDNF receptor or the integrin beta1 subunit.

CONCLUSIONS

In pancreatic cancer, the enhancement of integrin expression by GDNF signaling through the GDNF receptor strongly influences adhesion and invasion to ECM proteins.

Enhancement of integrins by interleukin-1alpha, and their relationship with metastatic and invasive behavior of human pancreatic ductal adenocarcinoma cells

BACKGROUND AND OBJECTIVES

Adhesion and invasion of tumor cells to extracellular matrix (ECM) proteins play an important role in tumor metastasis formation. We investigated the enhancement of adhesive and invasive behavior to ECM proteins of human pancreatic cancer cells by interleukin-1alpha (IL-1alpha) to examine the mechanism of adhesion and invasion of metastatic human pancreatic cancer cells to ECM proteins.

METHODS

The enhancement of integrin subunits by IL-1alpha was examined by cellular enzyme-linked immunosorbent assay (CELISA) in two metastatic human pancreatic cancer cell lines (BxPC-3 and SW1990) and two nonmetastatic pancreatic cancer cell lines (PaCa-2 and PANC-1). In addition, assays of cancer cell adhesion and invasion to ECM proteins were performed to investigate whether increased integrin expression affected the invasive interaction between cancer cells and the putative integrin ECM ligands.

RESULTS

Expression of the alpha6 subunit by metastatic cancer cells was enhanced by IL-1alpha. Metastatic cancer cells also exhibited preferential adherence and invasion to laminin compared with nonmetastatic cancer cells, and this was enhanced by IL-1alpha.

CONCLUSIONS

The enhancement of alpha6beta1-integrin by Il-1alpha acting through IL-1RI, as well as the expression of alpha6beta1-integrin, plays an important role in metastasis formation in pancreatic cancer

Gastrin mediated cholecystokinin-2 receptor activation induces loss of cell adhesion and scattering in epithelial MDCK cells

The presence of gastrin and CCK-2/gastrin receptors in human preneoplastic and neoplastic lesions of pancreas and colon suggests a role in cancer development. Gastrin's growth-promoting action has been established, but a role in cellular morphogenetic processes promoting tumor invasion has been elusive. Our aim was (i) to investigate whether activation of the CCK-2R affects cellular morphology, intercellular adhesion and motility, as crucial parameters of epithelial differentiation, and (ii) to identify the signaling pathways and mechanisms implicated. Madin-Darby Canine Kidney (MDCK) cells were chosen to generate an epithelial non-tumorigenic model system expressing human CCK-2R. Epithelial differentiation and motility were analysed upon CCK-2R activation using immunocytochemistry and invasion assays. The functionality of adhesion complexes and activity of signaling proteins was determined with biochemical techniques. CCK-2R activation induced cell dissociation and enhanced invasion, preceded by decreased membrane localization of adherens junction molecules and nuclear accumulation of beta-catenin. Concomitantly, and requiring the activation of several signaling pathways, catenins were shifted from the cytoskeletal to the cytoplasmic fraction, suggesting the detachment of the cytoskeleton from the adherens complex. These data represent the first evidence for the CCK-2R, regulating cell-cell and cell-substrate adhesion and support a role for CCK-2R in the progression of carcinoma.

Expression of thrombospondin-1 in human pancreatic adenocarcinomas: role in matrix metalloproteinase-9 production

Human pancreatic adenocarcinoma, an aggressive malignant disease, shows a strong desmoplastic reaction characterized by a remarkable proliferation of interstitial connective tissues. Thrombospondin-1 (TSP-1), a 450 kDa platelet and matrix glycoprotein, has been implicated in tumor invasion, angiogenesis and metastasis. TSP-1 and MMP-9 expression in pancreatic adenocarcinoma and control pancreas tissues was measured by immunohistochemistry. TSP-1 expression in pancreatic carcinoma cell lines, fibroblasts, and endothelial cells was measured by a competitive TSP-1 enzyme linked immunosorbent assay (ELISA). The effect of TSP-1 on MMP-9 production in pancreatic carcinoma cell lines was measured by zymography and Western blot analysis. Eighty five per cent (23/27) of cases of pancreatic adenocarcinoma showed increased TSP-1 staining in the desmoplastic stroma adjacent to tumor cells. No specific positive staining for TSP-1 was observed in the normal pancreatic tissues and the inflammatory areas. TSP-1 localized in tumor stroma surrounding the tumor cells expressing MMP-9. Using TSP-1 competitive ELISA, the secretion of TSP-1 by different pancreatic cancer cell lines into culture medium varied from 11.45 plus minus 14.08 to 275.82 plus minus 45.56 ng/10 6 cells/24 hours. The amounts of TSP-1 detected in both culture media and cell extracts from fibroblasts or endothelial cells were at least 2-3 fold higher than those from pancreatic cancer cells. TSP-1 augmented the production of matrix metalloproteinase-9, a matrix degrading enzyme, in pancreatic cancer cells in vitro. Stromally-derived TSP-1 up-regulates the production of MMP-9 by pancreatic adenocarcinoma. These data are consistent with the conclusion that TSP-1-rich stroma is involved in regulating matrix remodeling in tumor invasion.

Expression of ROCK-1 in human pancreatic cancer: its down-regulation by morpholino oligo antisense can reduce the migration of pancreatic cancer cells in vitro

INTRODUCTION

Invasion and metastasis of cancer cells require cell motility and adhesion. The small GTPase Rho and one of its effector molecules ROCK regulate cytoskeleton and actomyosin contractility, and play a crucial role in cell adhesion and motility. Results of previous studies showed that the elevated activity of ROCK-1, one of the isomers of ROCK kinases, led to an increase in the activity of invasion and metastasis of cancer cell lines.

AIM

To investigate the importance of ROCK-1 in cancer invasion and metastasis.

METHODOLOGY

We investigated the expression of ROCK-1 in two cancer cell lines and 31 human pancreatic tissues (21 pancreatic cancers [PC] and 10 histologically normal tissues) by immunoblotting and immunohistochemistry. We also examined by haptotaxis assay whether the migratory activity of PC cells could be suppressed by treatment with the morpholino antisense oligonucleotide in vitro.

RESULTS

The expression of ROCK-1 was found in 18 of 21 PC tissues (85.7%), but not in normal pancreatic tissues by immunoblotting and immunohistochemistry. Antisense oligo against ROCK-1 significantly inhibited the haptotaxis of Panc-1 in a dose-dependent manner, compared with the control oligo.

CONCLUSION

These results suggest that ROCK-1 may contribute to pancreatic cancer cell invasion and/or metastasis by facilitating cancer cell migration.

Myosin light chain kinase inhibitors can block invasion and adhesion of human pancreatic cancer cell lines

INTRODUCTION

Invasion and metastasis of pancreatic cancer (PC) require cell motility and adhesion, which depend on the activity of cytoskeleton. A cytoskeletal component indispensable for these processes is myosin II, the cytoplasmic analogue of smooth and skeletal muscle myosin.

AIMS AND METHODOLOGY

Because the activity of myosin II is accelerated by phosphorylation of myosin II on its regulatory light chain (RLC) by myosin light chain kinase (MLCK), we used two specific MLCK inhibitors, ML-7 and ML-9, for suppression of motility and adhesion of PC cell lines.

RESULTS

Both drugs were potent inhibitors, as measured by in vitro motility assay and adhesion assay. When treated with the same concentration of ML-7, the PC cells were rounded up, and the number of stress fibers was reduced markedly. The in vitro migration and adhesion of PC cells were inhibited by ML-7 and ML-9 in a dose-dependent manner, supporting a specific and competitive inhibition of MLCK by these drugs. The inhibition occurred at nontoxic concentrations.

CONCLUSIONS

These results highlight the importance of myosin II in the invasion and metastasis of PC cells and suggest the possibility that blocking of myosin II activity by a specific MLCK inhibitor may be a therapeutic strategy for preventing the invasion and metastasis of PC.

The cytotoxic effects of bile acids in crude bile on human pancreatic cancer cell lines

Pancreatic cancer frequently causes extrahepatic cholestasis. To identify the direct effects of bile acids in jaundiced serum on pancreatic cancer, the proliferation of PANC-1 and MIA PaCa-2 cells as well as the ultrastructural alteration of PANC-1 cells cultured in crude bile modified media were studied. The growth of these cells in the RPMI-1640 media with or without 1%, 2%, and 4% of the refined crude bile was assessed after 48 and 96 h of incubation. The ultrastructure of PANC-1 cells was investigated by scanning and transmission electron microscopy after 24 and 48 h of incubation. The proliferation of both cell lines in the bile-treated media was greatly inhibited. The inhibitory rates of bile on PANC-1 ranged from 24.1% +/- 3.3% to 66.9% +/- 6.6% (P < 0.01) and those on MIA PaCa-2 ranged from 16.7% +/- 3.8% to 50.7% +/- 5.5%. (P < 0.01). When the bile-added media were replaced, the cells were able to restore their proliferating ability. The PANC-1 cells incubated in the bile-supplied media indicated that the mirovilli, mitochondria, and other organelles had thus been injured. These results suggest that bile acids appear to inhibit the proliferation of PANC-1 and MIA PaCa-2 cells, and the probable inhibitory mechanism is mainly considered to be due to the cytotoxicity of such bile acids.

Gut peptide receptor expression in human pancreatic cancers

OBJECTIVE

To determine the prevalence of gastrointestinal (GI) peptide receptor expression in pancreatic cancers, and to further assess signaling mechanisms regulating neurotensin (NT)-mediated pancreatic cancer growth.

SUMMARY BACKGROUND DATA

Pancreatic cancer remains one of the leading causes of GI cancer death; novel strategies for the early detection and treatment of these cancers is required. Previously, the authors have shown that NT, an important GI hormone, stimulates the proliferation of an NT receptor (NTR)-positive pancreatic cancer.

METHODS

A total of 26 human pancreatic adenocarcinomas, obtained after resection, and 5 pancreatic cancer xenografts were analyzed for expression of NTR, vasoactive intestinal peptide receptor (VIPR), substance P receptor (SPR), and gastrin-releasing peptide receptor (GRPR). In addition, NTR expression, [Ca2+]i mobilization, and growth in response to NT was determined in L3.6, a metastatic pancreatic cancer cell line.

RESULTS

Neurotensin receptor was expressed in 88% of the surgical specimens examined and all five of the pancreatic cancer xenografts. In contrast, VIPR, SPR, and GRPR expression was detected in 31%, 27%, and 8% of pancreatic cancers examined, respectively. Expression of NTR, functionally coupled to the Ca2+ signaling pathway, was identified in L3.6 cells; treatment with NT (10 micromol/L) stimulated proliferation of these cells.

CONCLUSIONS

The authors demonstrated NTR expression in most of the pancreatic adenocarcinomas examined. In contrast, VIPR, SPR, and GRPR expression was detected in fewer of the pancreatic cancers. The expression of NTR and other peptide receptors suggests the potential role of endocrine manipulation in the treatment of these cancers. Further, the presence of GI receptors may provide for targeted chemotherapy or radiation therapy or in vivo scintigraphy for early detection.

Beta1 integrins play an essential role in adhesion and invasion of pancreatic carcinoma cells

To investigate the role of beta1 integrins in pancreatic carcinoma invasion, we analyzed the relationship between the activity of beta1 integrins and the invasive ability of human pancreatic carcinoma cell lines. AsPC1, BxPC3, PANC1, SU8686, KP1NL, KP2, and H48N cells had high expression of beta1 and alpha6 subunits, and various levels of alpha2, alpha3, and alpha5 expression as determined by flow cytometry. Cell adhesion assay revealed that alpha2beta1, alpha5beta1, and alpha6beta1 integrins were the predominant adhesion receptors for collagen, fibronectin, and laminin, respectively. Beta1 integrins on different cell types showed a wide range of constitutive activity. Anti-beta1 monoclonal antibody (MAB) TS2/16 rapidly activated beta1 integrins, and thus TS2/16 requirement in cell adhesion represented the levels of constitutive activity of beta1 integrins. Notably, as the result of in vitro chemoinvasion assay, the levels of constitutive activity of beta1 integrins correlated with the invasive ability of pancreatic carcinoma cells. The inhibitory anti-beta1 MAB 13 completely blocked the invasion of these cell lines. Alternatively, the stimulatory anti-beta1 MAB TS2/16 strongly inhibited the invasion. These results show an essential role of beta1 integrins in invasion of pancreatic carcinoma cells and also suggest subtle regulatory mechanisms of cell invasion.