Yin Yang-1 suppresses invasion and metastasis of pancreatic ductal adenocarcinoma by downregulating MMP10 in a MUC4/ErbB2/p38/MEF2C-dependent mechanism.

BACKGROUND: Increasing evidence indicates an important role of transcription factor Yin Yang-1 (YY1) in human tumorigenesis. However, its function in cancer remains controversial and the relevance of YY1 to pancreatic ductal adenocarcinoma (PDAC) remains to be clarified. METHODS: In this study, we detected YY1 expression in clinical PDAC tissue samples and cell lines using quantitative RT-PCR, immunohistochemistry and western blotting. We also detected MUC4 and MMP10 mRNA levels in 108 PDAC samples using qRT-PCR and analyzed the correlations between YY1 and MUC4 or MMP10 expression. The role of YY1 in the proliferation, invasion and metastatic abilities of PDAC cells in vitro was studied by CCK-8 assay, cell migration and invasion assays. In vivo pancreatic tumor growth and metastasis was studied by a xenogenous subcutaneously implant model and a tail vein metastasis model. The potential mechanisms underlying YY1 mediated tumor progression in PDAC were explored by digital gene expression (DGE) sequencing, signal transduction pathways blockage experiments and luciferase assays. Statistical analysis was performed using the SPSS 15.0 software. RESULTS: We found that the expression of YY1 in PDACs was higher compared with their adjacent non-tumorous tissues and normal pancreas tissues. However, PDAC patients with high level overexpression of YY1 had better outcome than those with low level overexpression. YY1 expression levels were statistically negatively correlated with MMP10 expression levels, but not correlated with MUC4 expression levels. YY1 overexpression suppressed, whereas YY1 knockdown enhanced, the proliferation, invasion and metastatic properties of BXPC-3 cells, both in vitro and in vivo. YY1 suppresses invasion and metastasis of pancreatic cancer cells by downregulating MMP10 in a MUC4/ErbB2/p38/MEF2C-dependent mechanism. CONCLUSIONS: The present study suggested that YY1 plays a negative role, i.e. is a tumor suppressor, in PDAC, and may become a valuable diagnostic and prognostic marker of PDAC.

Comprehensive analysis of the percentage of surface receptors and cytotoxic granules positive natural killer cells in patients with pancreatic cancer, gastric cancer, and colorectal cancer.

BACKGROUND: Digestive malignancies, especially pancreatic cancer (PC), gastric cancer (GC), and colorectal cancer (CRC), still occur at persistently high rates, and disease progression in these cancers has been associated with tumor immunosurveillance escape. Natural killer (NK) cell dysfunction may be responsible for this phenomenon, however, the exact relationship between tumor immunosurveillance escape in digestive malignancies and NK cell dysfunction remains unclear. METHODS: Percentage of the surface receptors NKG2A, KIR3DL1, NKG2D, NKp30, NKp44, NKp46, and DNAM-1, as well as the cytotoxic granules perforin and granzyme B positive NK cells were determined in patients with pancreatic cancer (n=31), gastric cancer (n=31), and CRC (n=32) prior to surgery and healthy controls (n=31) by multicolor flow cytometry. Independent t-tests or Mann-Whitney U-tests were used to compare the differences between the patient and healthy control groups, as well as the differences between patients with different pathologic features of cancer. RESULTS: Percentage of NKG2D, NKp30, NKp46, and perforin positive NK cells was significantly down-regulated in patients with PC compared to healthy controls, as well as GC and CRC; reduced levels of these molecules was associated with indicators of disease progression in each malignancy (such as histological grade, depth of invasion, lymph node metastasis). On the contrary, percentage of KIR3DL1 positive NK cells was significantly increased in patients with PC, as well as GC and CRC, but was not associated with any indicators of disease progression. CONCLUSIONS: Altered percentage of surface receptors and cytotoxic granules positive NK cells may play a vital role in tumor immunosurveillance escape by inducing NK cell dysfunction in patients with PC, GC, and CRC.

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

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Roles of Smad3 and Smad7 in rat pancreatic stellate cells activated by transforming growth factor-beta 1.

BACKGROUND: Pancreatic stellate cells (PSCs) play a major role in promoting pancreatic fibrosis. Transforming growth factor beta 1 (TGF-beta1) is a critical mediator of this process. This study aimed to determine the expression of the Smad3 and Smad7 genes in the process of PSC activation, and explore the mechanisms of chronic pancreatitis. METHODS: The expressions of Smad3 and Smad7 in PSCs before and after TGF-beta1 treatment were detected by reverse transcription-polymerase chain reaction and Western blotting analysis. Smad3 expression was detected in PSCs after treatment with 5 ng/ml of TGF-beta1 for 24 hours. RESULTS: Smad7 expression was decreased in TGF-beta1-activated PSCs (P<0.05) in a dose-dependent manner. When TGF-beta1 concentration reached 10 ng/ml, the expression of p-Smad3, Smad3, and Smad7 was inhibited (P<0.05). CONCLUSIONS: TGF-beta1 promotes the expression of Smad3 and inhibits the expression of Smad7 during the activation of PSCs. In contrast, high-dose TGF-beta1 downregulates the expression of Smad3 in completely activated PSCs.

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.

[Diagnosis and surgical treatment for non-functional islet cell tumor: a retrospective analysis of 44 cases].

OBJECTIVE: To evaluate the methods of diagnosis and surgical treatment for nonfunctional islet cell tumor (NICT). METHODS: Forty-four patients with non-functional islet cell tumor treated at the First Affiliated Hospital of Nanjing Medical University during January 1968 to June 2008 were analyzed retrospectively. There were 9 males and 35 females, aged from 7- to 70-years-old. Clinical manifestation: 15 cases (34.1%) of abdominal masses, 17 patients (38.6%) with epigastric or back pain, 5 cases of jaundice, 5 cases (11.4%) for upper abdominal fullness or vomiting, 10 cases (22.7%) of pancreatic tumor noticed by routine health checkups or imaging examinations. Imaging examination: CT scan, sonography, ERCP, MRI, upper GI series were performed in 33 (75.0%), 16 (36.4%), 6 (13.6%), 2 (4.5%), and 10 cases (22.7%) respectively. Operation methods: 39 patients (88.6%) underwent surgical resection and the other 5 patients did not. COMPLICATIONS: pancreatic fistula in 7 patients (15.9%), intra-abdominal bleeding in 4 (9.1%), gastrojejunal anastomosis outlet obstruction in 1 (2.3%), biliary fistula in 2 (4.5%) and incisional infection in 3 (6.8%). Surgery related mortality happened in 2 patients (4.5%), both treated before 1999. Twenty-five patients underwent operation between January 1999 and June 2008 were followed up for 6 to 108 months. All survive except one died 75 months after the surgery for unknown reason. CONCLUSIONS: No specific clinical manifestation is recognized for non-functional islet cell tumor. Spiral CT is an optimal diagnostic method, while surgery is the first choice for treatment. Middle segmental pancreatectomy has become an alternative surgical protocol for NICT.

[Therapeutic strategy for severe acute pancreatitis and pancreatic encephalopathy].

OBJECTIVE: To investigate the clinical treatment of pancreatic encephalopathy (PE) complicated in severe acute pancreatitis (SAP) patients. METHODS: Clinical data of 22 PE cases in 326 SAP patients admitted from January 1987 to December 2006 were collected and analyzed retrospectively. The incidence, clinical manifestation and therapy methods of PE were discussed respectively. RESULTS: All the cases were divided into 2 subgroups according to the changing of treatment strategy for SAP in the past 20 years. Thirteen cases of PE complicated in 114 SAP patients during the first decade (1987 - 1996) with the incidence of 11.4%, including eight early pancreatic encephalopathy (EPE) ones and five cases of delayed pancreatic encephalopathy (DPE). Only one patient survived and the mortality was 92.3%. During the second decade (1997 - 2006), nine cases of PE (all EPE) were observed in 212 SAP patients. The incidence was 4.2% and they all survived. Patients with PE usually presented with dysphoria, disturbance of orientation, lethargy, illusion and even coma. Physical examination of nerve system could find signs of meningeal irritation, increased intracranial pressure and elevated amylase in cerebrospinal fluid. Fungal infection and body fluid and metabolic disturbance frequently complicated in DPE patients. The total incidence was 6.6% (22/326) and mortality was 54.5% (12/22). Death mostly happened in the first ten years and all died with multiple organ failure. CONCLUSIONS: Elimination of different causes would be effective to decrease the incidence and intensive cerebral resuscitation and nerve nutrition therapy in the early stage is very important to decrease the mortality.

[Combined multiple organ resection in 16 patients with adenocarcinoma of the body or tail of the pancreas].

OBJECTIVE: To investigate the feasibility and therapeutic results of multiple organ resection in patients with tumor of the body and tail of pancreas. METHODS: The clinical and pathological data were analysed in 16 consecutive patients with neoplasm of the body and tail of pancreas from 1999 to 2004 retrospectively. RESULTS: Multiple organ resection was performed in 6 cases of primary pancreatic adenocarcinoma of the body and tail (3 cases of pancreatic cancer, 2 cases of malignant glucagonoma, and 1 case of well-differentiated pancreatic stromal sarcoma) and 10 cases of extrapancreatic malignancy (4 cases of gastric cancer, 2 cases of gastric leiomyosarcoma, 1 case of duodenal cancer, and 3 cases of colon cancer of hepatic flexure). Distal pancreatectomy with splenectomy was performed in all cases. In addition, 10 patients received splenic flexure colectomy, 6 patients received distal gastrectomy, 3 patients received left nephrectomy, left colectomy, total gastrectomy, liver lobe resection, left adrenalectomy, and local diaphragma resection, and 2 patients received transverse colectomy, subtotal colectomy, proximal proctectomy, proximal gastrectomy, and duodenectomy. No perioperative death and severe complications were observed. Patients with primary pancreatic cancer or pancreatic stromal sarcoma died within 1 year. Two patients with malignant glucagonoma died 51 and 39 months later. The 3-year survival rate was 70% in 10 patients with extrapancreatic malignancy, among which 2 patients with enteric cancer have survived 37 and 48 months. CONCLUSION: Radical combined multiple organ resection may be performed actively in appropriately selected patients.