Pancreatic Cancer Cell Line SW1990 Research Articles

Candidate immunogenic membrane antigens of human pancreatic cancer

To verify the obtained immunogenic membrane antigens candidate of pancreatic cancer in the performed research. Pancreatic cancer cell line SW1990 membrane protein underwent immunoblot with serum IgG purified from clinically collected sera of 66 pancreatic cancer patients. Number 3 and number 8 positive dots of immunoblot were identified by MALDI-TOF mass spectrometry and peptide mass fingerprinting matching. The candidate membrane antigens were further validated in cell lines by RT-PCR, real-time PCR and Western blot, and their different expression level of gene and protein in pancreatic cancer cell lines were contrastly studied. Number 3 and number 8 positive dots were identified as: voltage-dependent anion channel (VDAC3) and catechol-o-methyltransferase (COMT). RT-PCR, real-time PCR and Western blot showed that gene and protein of VDAC3 and COMT were expressed in the pancreatic cancer cell line SW1990, AsPc and P3 respectively. VDAC3 and COMT might be the candidate immunogenic membrane antigens of human pancreatic cancer, and their gene and protein are differently expressed in the pancreatic cancer cell line SW1990, AsPc and P3.

Establish a gemcitabine-resistant pancreatic cancer cell line SW1990/GZ and research the relationship between SW1990/GZ and pancreatic cancer stem cell

To establish a gemcitabine-resistant pancreatic cancer cell line SW1990/GZ, and to explore the relationship between drug-resistant cell line SW1990/GZ and pancreatic cancer stem cell. Gemcitabine-resistant pancreatic cancer cell line SW1990/GZ was obtained by treating parental cell line SW1990 in vitro with increasing dosage of gemcitabine in culture medium intermittently for 24 weeks. Stable cultures were obtained which were 77.2-fold increased in resistance relative to parental cells. Gene expressions of ABCB1/MDR1, ABCC1/MRP and ABCG2/BCRP were determined by real-time PCR. Tumorigenic potential was performed by nude mice xenograft transplant experiments. Side population analysis and CD24CD44 positive cells explore were determined by flow cytometry to examine cancer stem cell proportion. Gemcitabine-resistant cell line SW1990/GZ underwent obvious morphological and functional changes. Compared with the parental cell line, SW1990/GZ cell was small and turned into round shape. SW1990/GZ had a higher gene expression level of ABCB1/MDR1, ABCC1/MRP and ABCG2/BCRP than SW1990 (P < 0.01). Nude mice xenograft transplant experiments showed that only 1 × 10(5) SW1990/GZ cells were sufficient for tumor formation, whereas an injection of 1 × 10(5) SW1990 cells did not initiate tumors. Flow cytometry analysis showed that SP proportion in SW1990/GZ was (11.0 ± 1.0)%, whereas in parental SW1990 it was (4.6 ± 0.9)%, CD44CD24 positive cells was (8.73 ± 0.81)% in SW1990/GZ, whereas (1.1 ± 0.4)% in SW1990. Gemcitabine-resistant cell line SW1990/GZ has a higher proportion of pancreatic cancer stem cells compared to its parental cell line SW1990. CD44 is mainly responsible for acquired drug resistance, which can be a potential target to overcome acquired drug resistance in pancreatic cancer.

Side population in the pancreatic cancer cell lines SW1990 and CFPAC-1 is enriched with cancer stem-like cells

In this study, we first sought to determine the existence of side population (SP) cells in pancreatic cancer cell lines. Furthermore, we compared the biological characteristics of SP and non-SP cells. The presence of side population cells in pancreatic cancer cell lines was detected by Hoechst 33342 staining and FACS analysis. Cell cycle distribution was analyzed using flow cytometry. SP and non-SP cells were exposed to various concentrations of gemcitabine; drug sensitivity was examined using the MTT assay and flow cytometry using Annexin-V and PI staining. To compare the tumorigenic ability in vivo, groups of nude mice were orthotopically inoculated with varying numbers of SP and non-SP cells. The percentages of CD44+CD24+ and CD133+ in SP and non-SP cells were also detected by FACS analysis. The SP fraction was detected in BxPc-3, CFPAC-1, MIA PaCa-2, PANC-1 and SW1990 pancreatic cancer cell lines. Cell cycle analysis revealed that the SP cells contained more cells in the G1 phase and fewer cells in the S phase when compared with the non-SP cells. The SP cells exhibited increased tumorigenetic ability following in vivo transplantation into BALB/C nude mice and increased chemoresistance following in vitro exposure to gemcitabine. FACS analysis showed that the SP cells contained more CD44+CD24+ and CD133+ cells than the non-SP cells. In conclusion, these observations suggest that SP cells in the pancreatic cancer cell lines possess the property of cancer stem cells. SP cells may therefore be novel specific targets for the effective treatment of pancreatic cancer.

Preparation, physicochemical characterization and cytotoxicityin vitroof gemcitabine-loaded PEG-PDLLA nanovesicles

To investigate the preparation, physicochemical characterization and cytotoxicity in vitro of Gemcitabine-loaded poly(ethylene glycol)-block-poly(D,L-lactide) (PEG-PDLLA) nanovesicles. The nanovesicle carriers were prepared from the amphiphilic block copolymer of PEG-PDLLA by a double emulsion technique, and gemcitabine was used as the model drug. The morphology of the nanovesicles was determined by scanning and transmission electron microscopy, and the drug content, drug entrapment and drug-release curve in vitro were detected by UV-Vis-NIR spectrophotometry. Cytotoxicity in the human pancreatic cancer cell line SW1990 was tested by 3-(4,5-dimethyl) ethiazole (MTT) assay. The gemcitabine-loaded nanovesicles were hollow nanospheres with a mean size of 200.6 nm, drug loading of 4.14% and drug embedding ratio of 20.54%. The nanovesicles showed excellent controlled release that was characterized by a fast initial release during the first 72 h, followed by a slower and continuous release. The MTT assay demonstrated that gemcitabine-loaded nanovesicles exhibited dose-dependent and time-delayed cytotoxicity in the human pancreatic cancer cell line SW1990. Gemcitabine-loaded PEG-PDLLA nanovesicles prepared by a double emulsion technique exhibited good performance for controlled drug release, and had similar cytotoxic activity to free gemcitabine.

Proteomic Characterization of Human Erythrocyte 20S Proteasome and Analysis of Species-dependent 20S Proteasome Heterogeneity

Abstract A method for the purification of 20S proteasome (20S core particle, CP) was developed by combining differential centrifugations with nondenaturing polyacrylamide gel electrophoresis (native-PAGE), irrespective of species origins of CPs. CP purified from human erythrocytes was subjected to proteomic analysis by two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), revealing 33 spots of subunit isoforms with different molecular weights and isoelectric points. Furthermore, other four CPs were purified from yeast, mouse liver, and two pancreatic cancer cell lines SW1990 and PANC-1 using the method mentioned above and subjected to proteasome heterogeneity analysis by two-dimensional native/SDS-PAGE (native/sodium dodecyl sulphate polyacrylamide gel electrophoresis), in combination with CP from erythrocytes. In conclusion, the method described acts as a rapid and effective tool for CP isolations, and the results obtained may serve as a footstone for the investigations of species-dependent proteasome heterogeneity.

Research of immunogenic membrane antigens of pancreatic cancer

To screen and obtain the validate immunogenic membrane antigens in pancreatic cancer. Pancreatic cancer cell line SW1990 membrane protein was extracted and separated by two-dimensional gel electrophoresis (2-DE). One of the three parallel 2-DE gels underwent Coomassie blue staining while the other two underwent immunoblot. Serum IgG was purified from clinically collected sera of 66 pancreatic cancer patients and 24 chronic pancreatitis patients and used as the primary antibody of the immunoblot. Positive dots of immunoblot were identified by MALDI-TOF mass spectrometry and PMF matching. The candidate membrane antigens were further validated respectively in cell lines and tissues by RT-PCR, real-time PCR, Western blot, and their different expression level of gene and protein between pancreatic cancer cell line and normal pancreatic tissue were compared studied. The immunoblot of SW1990 membrane protein with serum IgG from cancer patients showed nine positive dots which were not the same as those from immunoblot with serum IgG from chronic pancreatitis patients. One talent dot was identified with MALDI and PMF as VDAC2. RT-PCR and real-time PCR showed that the gene of VDAC2 was expressed in the pancreatic cancer cell line. Western blot showed that the expression of protein level of VDAC2 in the pancreatic cancer cell line was obviously higher than in normal pancreatic tissue. VDAC2 might be the candidate immunogenic membrane antigens of pancreatic cancer, and its gene is all expressed in the pancreatic cancer cell line SW1990, AsPc and P3. The protein level of VDAC2 is significantly overexpressed in pancreatic cancer cell line than in normal pancreatic tissue.

Dual role of Ski in pancreatic cancer cells: tumor-promoting versus metastasis-suppressive function

Ski used to be defined as an oncogene that contributes to the resistance of tumor cells to transforming growth factor-beta (TGF-beta)-induced growth arrest. As TGF-beta has a dual effect on tumor growth with both tumor-suppressing and -promoting activity depending on the stage of carcinogenesis and the cell type, the precise role of Ski in carcinogenesis remains unclear. In this study, we show that downregulation of Ski through lentivirus-mediated RNA interference decreases tumor growth both in vitro and in vivo, yet promotes cell invasiveness in vitro, and lung metastasis in vivo in the pancreatic cancer cell line SW1990, which contain wild-type Smad4 expression, and the BxPC3 cell line, which is Smad4 deficient. We also show that the downregulation of Ski increases TGF-beta-induced transcriptional activity, which is associated with increased TGF-beta-dependent Smad2/3 phosphorylation, and results in an altered expression profile of TGF-beta-inducible genes involved in metastasis, angiogenesis and cell proliferation and epithelial-mesenchymal transition. Immunohistochemical analysis of specimens from 71 patients with pancreatic adenocarcinoma showed a significant association between overexpression of Ski and decreased patient survival time (P = 0.0024). Our results suggest that Ski may act as a tumor proliferation-promoting factor or as a metastatic suppressor in human pancreatic cancer.

Phosphoinositide 3‐kinase inhibitor (wortmannin) inhibits pancreatic cancer cell motility and migration induced by hyaluronan in vitro and peritoneal metastasis in vivo

In order to block peritoneal metastasis of pancreatic cancer cells, we have attempted to block the signal transduction pathway involving hyaluronan (HA), Src, phosphoinositide 3-kinase (PI3K) and Akt. We examined the effects of Src, PI3K and Akt inhibitors on pancreatic cancer cell motility, invasion and metastasis. The pancreatic cancer cell line SW1990, known to cause peritoneal metastasis efficiently in nude mice, was used in this study. SW1990 cells were stimulated by HA to induce Akt phosphorylation. Then, the inhibitory effects of PI3K and Src kinase inhibitors were examined. Cell motility and cell migration assays were adopted to assess the cancer cell motility and its migration capability. We also examined the therapeutic efficacies of PI3K inhibitor wortmannin on peritoneal metastasis of SW1990 cells in the nude mouse model. Stimulation of SW1990 cells by HA markedly induced the Src-PI3K-Akt signaling, thus enhancing cancer cell motility and its migration. Significantly, we found that wortmannin could exert marked inhibition of the peritoneal metastasis of SW1990 in nude mice in vivo. These findings indicate that the PI3K-Akt signaling pathway plays an essential role in peritoneal metastasis and PI3K inhibitors such as wortmannin can be novel modalities to prevent peritoneal metastasis of invasive cancers such as pancreatic cancer.

Inhibitory effects of docosahexaenoic acid on the growth of incubated human pancreatic cancer cell lines

Objective To investigate the effects of docosahexaenoic acid (DHA) on the growth of human pancreatic cancer cell lines. Methods Human pancreatic cancer cell lines Patu8988 and SW1990 were treated with DHA. The cell proliferation was evaluated by MTT assay. Cell cycle, apoptosis, and cyclooxygenase-2 ex-pression were evaluated by flow cytometry. Results After incubation of pancreatic cancer cell with DHA for 24 to 72 hours, cell proliferation significantly decreased (P<0. 01) and apoptosis increased, both of which were time- dependent and dose-dependent After incubation with 50μg/ml DHA for 24 hours, cyclooxygenase-2 expression of pancreatic cancer cell lines significantly decreased (P < 0. 05). Conclusions DHA can inhibit the growth of hu- man pancreatic cancer cells via decreasing cell proliferation and inducing apoptosis. These effects may be associat- ed with the decrease of cyclooxygenase-2 expression. Key words: Docosahexaenic acid; Pancreatic cancer; Cell apoptosis; Cyclooxygenase-2

ERK signaling pathway may induce gemcitabine chemoresistance in pancreatic cancer cell line SW1990 by regulating the expression of mdr-1 and RRM1 gene

Objective To investigate the relationship between extracellular signal-regulated kinase (ERK) pathway, multidrug resistance gene (mdr-1), ribonucleotide reductase M1 (RRM1) gene and their roles in gemcitabine (GEM) chemoresistance in pancreatic cancer cell line SW1990.

Synergetic anticancer effect of combined gemcitabine and photodynamic therapy on pancreatic cancer in vivo

To investigate the anti-tumor effects of combined cytotoxic drug (gemcitabine) and photodynamic therapy (PDT) on human pancreatic cancer xenograft in nude mice. Human pancreatic cancer cell line SW1990 was used in the investigation of the in vivo effect of combined gemcitabine and PDT on human pancreatic cancer xenograft in mice. Sixty mice were randomly allocated into a control group (without treatment), photosensitizer treatment group (2 mg/kg photosan, without illumination), chemotherapy group (50 mg/kg gemcitabine i.p.), PDT group (2 mg/kg photosan + laser irradiation) and combined treatment group (photosan + chemotherapy), with 12 mice in each group. Tumor size was measured twice every week. Anti-tumor activity in different groups was evaluated by tumor growth inhibition (TGI). No significant anti-tumor effect was observed either in photosensitizer treatment group or in chemotherapy group. PDT led to necrosis in cancer lesions and significantly reduced tumor volume compared with photosensitizer on day 6 and at the following time points after initialization of therapy (0.24 +/- 0.15-0.49 +/- 0.08 vs 0.43 +/- 0.18-1.25 +/- 0.09, P < 0.05). PDT significantly reduced tumor volume in combined treatment group compared with photosensitizer treatment group (0.12 +/- 0.07-0.28 +/- 0.12 vs 0.39 +/- 0.15-1.20 +/- 0.11, P < 0.05), small dose chemotherapy group (0.12 +/- 0.07-0.28 +/- 0.12 vs 0.32 +/- 0.14-1.16 +/- 0.08, P < 0.05) and control group (0.12 +/- 0.07-0.28 +/- 0.12 vs 0.43 +/- 0.18-1.25 +/- 0.09, P < 0.05). TGI was higher in the combined treatment group (82.42%) than in the PDT group (58.18%). PDT has a significant anti-tumor effect, which is maintained for a short time and can be significantly enhanced by small doses of gemcitabine.

Pancreatic stellate cells promote proliferation and invasiveness of human pancreatic cancer cells via galectin-3

To investigate the role of pancreatic stellate cells (PSCs) and galectin-3 (GAL-3) in the proliferation and infiltration of pancreatic cancer cell line SW1990. Human pancreatic cancer cell line SW1990 and PSCs were cultured in vitro. Supernatant fluid of cultured PSCs and SW1990 cells was collected. Expression of GAL-3 in SW1990 cells and PSCs was detected by ELISA, RT-PCR and Western blotting. Proliferation of cultured PSCs and SW1990 cells was measured by 3-(4, 5-methylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and flow cytometry. Infiltration of SW1990 cells was detected by a cell infiltration kit. SW1990 cells expressed GAL-3 and this was up-regulated by the supernatant fluid of cultured PSCs. PSCs did not express GAL-3. SW1990 cells stimulated proliferation of PSCs via GAL-3. GAL-3 antibody inhibited SW1990 cell proliferation, while the supernatant fluid of PSCs stimulated proliferation of SW1990 cells through interaction with GAL-3 protein. The supernatant fluid of PSCs enhanced the invasiveness of SW1990 cells through interaction with GAL-3. GAL-3 and PSCs were involved in the proliferation and infiltration process of pancreatic cancer cells.

Apoptosis of human pancreatic cancer cells induced by Triptolide

To investigate apoptosis in human pancreatic cancer cells induced by Triptolide (TL), and the relationship between this apoptosis and expression of caspase-3' bcl-2 and bax. Human pancreatic cancer cell line SW1990 was cultured in DMEM media for this study. MTT assay was used to determine the cell growth inhibitory rate in vitro. Flow cytometry and TUNEL assay were used to detect the apoptosis of human pancreatic cancer cells before and after TL treatment. RT-PCR was used to detect the expression of apoptosis-associated gene caspase-3' bcl-2 and bax. TL inhibited the growth of human pancreatic cancer cells in a dose-and time-dependent manner. TL induced human pancreatic cancer cells to undergo apoptosis with typically apoptotic characteristics. TUNEL assay showed that after the treatment of human pancreatic cancer cells with 40 ng/mL TL for 12 h and 24 h, the apoptotic rates of human pancreatic cancer cells increased significantly. RT-PCR demonstrated that caspase-3 and bax were significantly up-regulated in SW1990 cells treated with TL while bcl-2 mRNA was not. TL is able to induce the apoptosis in human pancreatic cancer cells. This apoptosis may be mediated by up-regulating the expression of apoptosis-associated caspase-3 and bax gene.

Effect of antidepressants on body weight, ethology and tumor growth of human pancreatic carcinoma xenografts in nude mice

To investigate the effects of mirtazapine and fluoxetine, representatives of the noradrenergic and specific serotonergic antidepressant (NaSSA) and selective serotonin reuptake inhibitor (SSRI) antidepressant respectively, on body weight, ingestive behavior, locomotor activity and tumor growth of human pancreatic carcinoma xenografts in nude mice. A subcutaneous xenograft model of human pancreatic cancer cell line SW1990 was established in nude mice. The tumor-bearing mice were randomly divided into mirtazapine group (10 mg/kg per day), fluoxetine group (10 mg/kg per day) and control group (an equivalent normal saline solution) (7 mice in each group). Doses of all drugs were administered orally, once a day for 42 d. Tumor volume and body weight were measured biweekly. Food intake was recorded once a week. Locomotor activity was detected weekly using an open field test (OFT). Compared to the fluoxetine, mirtazapine significantly increased food intake from d 14 to 42 and attenuated the rate of weight loss from d 28 to 42 (t = 4.38, P < 0.05). Compared to the control group, food intake was significantly suppressed from d 21 to 42 and weight loss was promoted from d 35 to 42 in the fluoxetine group (t = 2.52, P < 0.05). There was a significant difference in body weight of the mice after removal of tumors among the three groups. The body weight of mice was the heaviest (13.66 +/- 1.55 g) in the mirtazapine group and the lightest (11.39 +/- 1.45 g) in the fluoxetine group (F( (2,12) ) = 11.43, P < 0.01). The behavioral test on d 7 showed that the horizontal and vertical activities were significantly increased in the mirtazapine group compared with the fluoxetine and control groups (F( (2,18) ) = 10.89, P < 0.01). These effects disappeared in the mirtazapine and fluoxetine groups during 2-6 wk. The grooming activity was higher in the mirtazapine group than in the fluoxetine group (10.1 +/- 2.1 vs 7.1 +/- 1.9 ) (t = 2.40, P < 0.05) in the second week. There was no significant difference in tumor volume and tumor weight of the three groups. Mirtazapine and fluoxetine have no effect on the growth of pancreatic tumor. However, mirtazapine can significantly increase food intake and improve nutrition compared with fluoxetine in a pancreatic cancer mouse model.

Metformin induces apoptosis of pancreatic cancer cells

To assess the role and mechanism of metformin in inducing apoptosis of pancreatic cancer cells. The human pancreatic cancer cell lines ASPC-1, BxPc-3, PANC-1 and SW1990 were exposed to metformin. The inhibition of cell proliferation and colony formation via apoptosis induction and S phase arrest in pancreatic cancer cell lines of metformin was tested. In each pancreatic cancer cell line tested, metformin inhibited cell proliferation in a dose dependent manner in MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assays). Flow cytometric analysis showed that metformin reduced the number of cells in G1 and increased the percentage of cells in S phase as well as the apoptotic fraction. Enzymelinked immunosorbent assay (ELISA) showed that metformin induced apoptosis in all pancreatic cancer cell lines. In Western blot studies, metformin induced poly-ADP-ribose polymerase (PARP) cleavage (an indicator of caspase activation) in all pancreatic cancer cell lines. The general caspase inhibitor (VAD-fmk) completely abolished metformin-induced PARP cleavage and apoptosis in ASPC-1 BxPc-3 and PANC-1, the caspase-8 specific inhibitor (IETD-fmk) and the caspase-9 specific inhibitor (LEHD-fmk) only partially abrogated metformin-induced apoptosis and PARP cleavage in BxPc-3 and PANC-1 cells. We also observed that metformin treatment dramatically reduced epidermal growth factor receptor (EGFR) and phosphorylated mitogen activated protein kinase (P-MAPK) in both a time- and dose-dependent manner in all cell lines tested. Metformin significantly inhibits cell proliferation and apoptosis in all pancreatic cell lines. And the metformin-induced apoptosis is associated with PARP cleavage, activation of caspase-3, -8, and -9 in a time- and dose-dependent manner. Hence, both caspase-8 and -9-initiated apoptotic signaling pathways contribute to metformin-induced apoptosis in pancreatic cell lines.

Selection of genes related to multidrug resistance of pancreatic ductal adenocarcinoma by microarray analysis

To investigate the genes concerning multidrug resistance (MDR) of pancreatic ductal adenocarcinoma with microarray analysis. Gene expression profile of pancreatic cancer cell line SW1990 and resistance subline SW1990/5-FU, SW1990/ADM, SW1990/GEM were screened in two independent replicates using oligonucleotide microarray (Affymetrix HG U133 2.0 plus) which contained 38,500 human genes. And advanced bioinformatics analysis was conducted. Totally, 165 genes and expressed sequence tags (ESTs), which were seldom reported to be related with drug resistance before,were statistically difference and the fold change was up- or down-regulated at least 2 folds in all 3 resistant sub-lines when compared with SW1990. According gene ontology, the genes related to oxidoreductase activity, apoptosis, cell cycle, signal transduction and cell adhesion might be some epigenetic changes for MDR development. Hierarchical clustering analysis, showed several interesting clusters, namely, TNKS2, PRDX4 and CCDC4. MDR of pancreatic cancer is a complicated and multifactorial process. In the present study, a widespread differential gene expression pattern was constructed in PDAC multidrug resistant cells. Advanced study will provide new targets for MDR research and cast insights into research of the molecular mechanism of MDR.

Modulatory effects of EPA and DHA on proliferation and apoptosis of pancreatic cancer cells

In order to investigate the effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on the proliferation, apoptosis of pancreatic cancer cell line SW1990 cells and the expression of cyclin E mRNA, the SW1990 cells were treated with different concentrations of EPA or DHA (20, 40, 60 microg/mL) for 0, 12, 24, 36 and 48 h respectively. By using MTT method, the inhibitory effects of EPA or DHA on the cell growth were assayed. Real time PCR was used to detect the expression changes of cyclin E mRNA after the SW1990 cells were treated with 40 microg/mL EPA or DHA for different time. Flow cytometry was used to test the changes of apoptostic rate in the SW1990 cells treated with different concentrations of EPA or DHA for 24 h. The results showed that EPA and DHA could inhibit the growth of SW1990 cells in a time-and concentration-dependent manner (P<0.01). EPA or DHA could also significantly inhibit the expression of cyclin E mRNA in a time-dependent manner (P<0.05). EPA or DHA could induce the apoptosis of SW1990 cells in a concentration-dependent manner (P<0.01). It was concluded that omega-3 fatty acid could inhibit the proliferation of pancreatic cancer cell line SW1990 cells and promote their apoptosis. The down-regulation of the cyclin E expression by omega-3 fatty acid might be one of the mechanisms for its anti-tumor effect on pancreatic cancer.

RNA interference‐mediated signal transducers and activators of transcription 3 gene silencing inhibits invasion and metastasis of human pancreatic cancer cells

Signal transducers and activators of transcription-3 (STAT3), a central cytoplasmic transcription factor, is frequently overexpressed and constitutively activated by tyrosine during malignant transformation. The overexpression and phosphorylation of STAT3 in pancreatic cancer has been described only recently, but the roles and mechanism still remain unclear. In this study, we elucidate the significance of the STAT3 signaling pathway in metastatic potentials of pancreatic cancer. We stably silence the expression of the STAT3 and p-STAT3 by using RNA interference (RNAi) in the pancreatic cancer cell line SW1990, and then reduce its invasion capacity in vitro and metastasis capacity in vivo compared to parental cells or cells tansfected with a control vector. Furthermore, silencing SW1990 cells with the STAT3 gene by RNAi also led to a decrease of matrix metalloproteinases-2 (MMP-2) and vascular endothelial growth factor (VEGF) at the mRNA and protein level. Collectively, these studies suggest that activation of the STAT3 signaling pathway plays an important role in the progression of pancreatic cancer, and that silence of the STAT3 gene with RNAi may be a useful anti-invasive therapeutic option in pancreatic cancer.

Down regulation of mitogen activated protein kinase phosphatase-1 mediate acquired multidrug resistance in pancreatic adenocarcinoma cell line SW1990/Fu

To investigate the role of mitogen activated protein kinase phosphatase-1 (MKP-1) in mediating acquired multidrug resistance in pancreatic adenocarcinoma cell line SW1990/Fu. To detect MKP-1 mRNA expression, Northern blot analysis was carried out in well established drug resistant pancreatic adenocarcinoma cell line SW1990/Fu, SW1990 and MiaPaCa-2 cell lines. To further elucidate the exact role of MKP-1, Western blot hybridization was performed in these three cell lines. Northern blot analysis of total RNA isolated from SW1990/Fu, SW1990 and MiaPaCa-2 cell lines revealed the presence of the 2400 bp MKP-1 transcript 7 at relatively high levels in pancreatic cancer cell lines SW1990 and MiaPaCa-2. In the SW1990/Fu, the MKP-1 transcript was detectable at very low level. Densitometric analysis with normalization to 7S indicated that MKP-1 mRNA expression level was significantly decreased in SW1990/Fu in comparison with the parental and MiaPaCa-2 cell lines. MKP-1 protein expression level in SW1990/Fu detected by Western blot was coincident with mRNA level. MKP-1 may be involved in acquired multidrug resistance in pancreatic adenocarcinoma, and we could hypothesized that alterations of intra-cellular transduction signal system acts as an important role in multidrug resistance of tumor cells.

Inhibitory effects of antisence haparanase gene on proliferation and invasion of human pancreatic cancer cell line SW1990 in vitro

Inhibitory effects of antisence haparanase gene on proliferation and invasion of human pancreatic cancer cell line SW1990 <i>in vitro</i>