[Expression and Role of PD-L1 in a Mouse Model of Necrotizing Enterocolitis].

Objective: To investigate the expression and role of programmed death ligand-1 (PD-L1) in a mouse model of necrotizing enterocolitis (NEC). Methods: A total of 20 wild-type C57 BL/6 J mice were randomly assigned to the control and the model groups. Mice in the control group were breastfed, while mice in the model group were given lipopolysaccharide, formula feeding, hypoxia, and cold stimulation for NEC induction. Then, the intestines of the mice were collected in order to assess the pathological changes through HE staining, to examine PD-L1 expression and localization with immunofluorescence co-localization, and to evaluate intestinal PD-L1 expression with Western blot. Peripheral blood was collected for flow cytometry to examine leukocyte subpopulations and their PD-L1 expression. On the other hand, 14 PD-L1 (+/+) mice and 14 PD-L1 (-/-) mice were randomly divided into their respective genotype control groups and model groups. The same induction method as was already mentioned was adopted for the model groups. The intestines of the mice were collected for HE staining to evaluate the pathological change and peripheral blood was collected to examine the expression of inflammatory factors. Results: The NEC mouse model was successfully constructed. PD-L1 was widely expressed in enterocytes and inflammatory cells in the mouse intestines and in T cells, monocytes, and neutrophils in peripheral blood. The expression of PD-L1 in NEC mouse intestines increased in comparison with that of the control group. In the peripheral blood of NEC mice, the proportion of T cells and monocytes and their PD-L1 expression showed no significant changes compared with those of the control group, while the proportion of neutrophils and their PD-L1 expression increased by about 140% and 150%, respectively, in comparison with those of the control group ( P<0.05). According to the results of the PD-L1 gene mouse experiment, the control groups of PD-L1 (+/+) mice and PD-L1 (-/-) mice showed no significant difference in their intestinal conditions and serum inflammatory factor levels, while the PD-L1 (-/-) NEC mouse had worse intestinal pathological changes and increased mean pathological scores compared with those of PD-L1 (+/+) NEC mouse ( P<0.05). In addition, serum interleukin (IL)-10 in PD-L1 (-/-) NEC mouse decreased by about 44% compared with that of PD-L1 (+/+) NEC mice, and chemokine (C-X-C motif) ligand 1/IL-6/IL-1ß all increased by more than 25% (all P<0.05). Conclusion: PD-L1 is widely expressed in inflammatory cells and enterocytes in mice. Knocking out PD-L1 aggravates the degree of NEC inflammation and intestinal pathological changes. PD-L1 plays a protective role by reducing inflammation in the pathogenesis of NEC, the mechanism of which may be related to the regulation of neutrophils/enterocytes.

[An Improved Acute Pancreatitis Apoptosis/Necrosis In vitro Model of Acinar Cells].

OBJECTIVE: To improve the apoptosis/necrosis In vitromodel of ascites-induced acute pancreatitic (AP) acinar cells by using the co-culture system and mixed ascites technology for the first time. Furthermore, we compared this improved model with cerulein and cerulein+LPS models, and observed the effects of three models on acinar apoptotic/necrotic-related indicators. METHODS: The In vitrocultured rat acinar cells AR42J were divided in four groups: control group (medium+PBS), cerulein group (medium+10 nmol/L cerulein), cerulein+LPS group (medium+10 nmol/L cerulein+10 mg/L LPS) and improved ascites group. In the improved ascites group, the ascites of sodium taurocholate-induced rat model was mixed and added into the co-culture system to stimulated In vitrocultured homogenous acinar cells. The co-culture system was set as follows: the chambers with the pore size of 1 µm were placed in the cultue plate, and the culture medium and mixed ascites were respectively added to the culture plate and the chamber at a ratio of 1:1. The acinar cells in each group were collected after 24 h stimulation. The apoptotic/necrotic rates, the expressions of apoptosis/necrosis related proteins [B-cell lymphoma protein 2 (Bcl-2), Bcl-2-associated X protein (Bax) and receptor interacting protein 1 (RIP1)], and the ultra-structure of acinar cells were detected by flow cytometry, Western blot and transmission electron microscopy (TEM). RESULTS: The acinar cells in the improved ascites model were mainly characterized by necrosis; compared with the other 3 groups, the apoptosis rate and necrosis rate were both up-regulated, RIP1 and BAX protein expression levels were up-regulated, and Bcl-2 protein was down-regulated. TEM results showed the organelle structure of acinar cells was destroyed, and the cell membrane was degraded in the improved ascites model. Compared with the control group, apoptosis rate of acinar cells in the cerulein and cerulein+LPS models were increased and necrosis rate were not changed. The expression of pro-apoptotic protein Bax was increased, while the expression level of RIP1 was not significantly increased. TEM results showed that in cerulein group and cerulein+LPS group, the chromatin of the cells was condensed into a mass, the cytoplasm was degraded and the cell membrane was intact, showing typical apoptosis characteristics. CONCLUSION: Compared with cerulein and cerulein +LPS models, which mainly focus on apoptosis of acinar cells and applied to mild acute pancreatitis study, the improved ascites model mainly focuses on the necrosis of acinar cells and is a good model for studying acinar cell necrosis and severe acute pancreatitis.

Comparative transcriptome and proteome profiling of two Citrus sinensis cultivars during fruit development and ripening.

BACKGROUND: Transcriptome and proteome analyses on fruit pulp from the blood orange 'Zaohong' and the navel orange 'twenty-first century' were performed to study Citrus sinensis quality-related molecular changes during consecutive developmental periods, including young fruit, fruit-coloring onset and fruit delayed-harvest for two months, during which fruit remained on the trees. RESULTS: The time-course analysis for the fruit developmental periods indicated a complex, dynamic gene expression pattern, with the numbers of differentially expressed genes (DEGs) between the two cultivars being 119, 426 and 904 at the three continuous stages tested during fruit development and ripening. The continuous increase in total soluble solids over the course of fruit development was correlated with up-regulated sucrose phosphate synthase (SPS) transcription levels in both cultivars. Eleven differentially expressed genes between the two cultivars involved in the flavonoid pathway were significantly enriched at the onset of the fruit-coloring stage when anthocyanins were detected in blood orange alone. Among 5185 proteins, 65 up-regulated and 29 down-regulated proteins were co-expressed with their cognate mRNAs with significant transcription and protein expression levels when the fruits from the two cultivars were compared at the fruit delayed-harvest stage. Additionally, important genes participating in the γ-aminobutyric acid (GABA) shunt were activated in blood orange at two significant expression levels in the fruit delayed-harvest stage. Thus, organic acids in fruit continuously decreased during this stage. CONCLUSIONS: This research was the first to provide a more comprehensive understanding of the differentially expressed genes involved in anthocyanin, sucrose and citrate metabolism at the transcriptome and proteome levels in C. sinensis, especially during the fruit delayed-harvest stage.

Resolvin D1 protects against inflammation in experimental acute pancreatitis and associated lung injury.

Acute pancreatitis is an inflammatory condition that may lead to multisystemic organ failure with considerable mortality. Recently, resolvin D1 (RvD1) as an endogenous anti-inflammatory lipid mediator has been confirmed to protect against many inflammatory diseases. This study was designed to investigate the effects of RvD1 in acute pancreatitis and associated lung injury. Acute pancreatitis varying from mild to severe was induced by cerulein or cerulein combined with LPS, respectively. Mice were pretreated with RvD1 at a dose of 300 ng/mouse 30 min before the first injection of cerulein. Severity of AP was assessed by biochemical markers and histology. Serum cytokines and myeloperoxidase (MPO) levels in pancreas and lung were determined for assessing the extent of inflammatory response. NF-κB activation was determined by Western blotting. The injection of cerulein or cerulein combined with LPS resulted in local injury in the pancreas and corresponding systemic inflammatory changes with pronounced severity in the cerulein and LPS group. Pretreated RvD1 significantly reduced the degree of amylase, lipase, TNF-α, and IL-6 serum levels; the MPO activities in the pancreas and the lungs; the pancreatic NF-κB activation; and the severity of pancreatic injury and associated lung injury, especially in the severe acute pancreatitis model. These results suggest that RvD1 is capable of improving injury of pancreas and lung and exerting anti-inflammatory effects through the inhibition of NF-κB activation in experimental acute pancreatitis, with more notable protective effect in severe acute pancreatitis. These findings indicate that RvD1 may constitute a novel therapeutic strategy in the management of severe acute pancreatitis.

Effects of Tocilizumab on Experimental Severe Acute Pancreatitis and Associated Acute Lung Injury.

OBJECTIVE: To examine the therapeutic effects of tocilizumab, an antibody against interleukin-6 receptor, on experimental severe acute pancreatitis and associated acute lung injury. The optimal dose of tocilizumab and the activation of interleukin-6 inflammatory signaling were also investigated. DESIGN: Randomized experiment. SETTING: Research laboratory at a university hospital. SUBJECT: Experimental severe acute pancreatitis in rats. INTERVENTIONS: Severe acute pancreatitis was induced by retrograde injection of sodium taurocholate (50 mg/kg) into the biliopancreatic duct. In dose-study, rats were administered with different doses of tocilizumab (1, 2, 4, 8, and 16 mg/kg) through the tail vein after severe acute pancreatitis induction. In safety-study, rats without severe acute pancreatitis induction were treated with high doses of tocilizumab (8, 16, 32, and 64 mg/kg). Serum and tissue samples of rats in time-study were collected for biomolecular and histologic evaluations at different time points (2, 6, 12, 18, and 24 hr). MEASUREMENTS AND MAIN RESULTS: 1) Under the administration of tocilizumab, histopathological scores of pancreas and lung were decreased, and severity parameters related to severe acute pancreatitis and associated lung injury, including serum amylase, C-reactive protein, lung surfactant protein level, and myeloperoxidase activity, were all significant alleviated in rat models. 2) Dose-study demonstrated that 2 mg/kg tocilizumab was the optimal treatment dose. 3) Basing on multi-organ pathologic evaluation, physiological and biochemical data, no adverse effect and toxicity of tocilizumab were observed in safety-study. 4) Pancreatic nuclear factor-κB and signal transducer and activator of transcription 3 were deactivated, and the serum chemokine (C-X-C motif) ligand 1 was down-regulated after tocilizumab administration. CONCLUSIONS: Our study demonstrated tocilizumab, as a marketed drug commonly used for immune-mediated diseases, was safe and effective for the treatment of experimental severe acute pancreatitis and associated acute lung injury. Our findings provide experimental evidences for potential clinical application of tocilizumab in severe acute pancreatitis and associated complications.

PD-L1 blockade in mitigating severe acute pancreatitis induced pancreatic damage through modulation of immune cell apoptosis.

Acute pancreatitis (AP) is a prevalent gastrointestinal disorder. The immune response plays a crucial role in AP progression. However, the impact of immune regulatory checkpoint PD-L1 on severe acute pancreatitis (SAP) remains uncertain. Hence, this study aimed to examine the influence of PD-L1 on SAP. We assessed PD-L1 expression in neutrophils and monocytes obtained from SAP patients. We induced SAP in C57BL/6J mice, PD-L1 gene-deficient mice, and PD-L1 humanized mice using intraperitoneal injections of cerulein plus lipopolysaccharide. Prior to the initial cerulein injection, a PD-L1 inhibitor was administered. Pancreatic tissues were collected for morphological and immunohistochemical evaluation, and serum levels of amylase, lipase, and cytokines were measured. Flow cytometry analysis was performed using peripheral blood cells. The expression of PD-L1 in neutrophils and monocytes was significantly higher in SAP patients compared to healthy individuals. Likewise, the expression of PD-L1 in inflammatory cells in the peripheral blood of SAP-induced C57BL/6J mice was notably higher than in the control group. In mice with PD-L1 deficiency, SAP model exhibited lower pancreatic pathology scores, amylase, lipase, and cytokine levels compared to wild-type mice. PD-L1 deletion resulted in reduced neutrophil apoptosis, leading to an earlier peak in neutrophil apoptosis. Furthermore, it decreased early monocyte apoptosis and diminished the peak of T lymphocyte apoptosis. Within the SAP model, administration of a PD-L1 inhibitor reduced pancreatic pathology scores, amylase, lipase, and cytokine levels in both C57BL/6J mice and PD-L1 humanized mice. These findings suggest that inhibiting PD-L1 expression can alleviate the severity of SAP.

The ER chaperone GRP78 is associated with the severity of cerulein-induced pancreatic inflammation via regulating apoptosis of pancreatic acinar cells.

BACKGROUND/AIMS: To study the potential role of the 78kDa glucose regulated protein (GRP78) in the pathogenesis of acute pancreatitis (AP) in vitro. METHODOLOGY: AR42J cells were stimulated by cerulein or cerulein plus lipoplysaccharide (LPS). The severity of pancreatic inflammation was evaluated by amylase, lipase, TNF-a, and IL-6. Apoptosis was determined by flow cytometry; the expressions of apoptotic genes, GRP78 and the downstream molecules were determined by real-time quantitative PCR and Western blot. RESULTS: After cerulein stimulation, the levels of amylase, lipase, TNF-a and IL-6 were all increased, with a more pronounced increase after cerulein plus LPS stimulation. Apoptosis was different in two cell models, high apoptosis in cerulein group; whereas cerulein plus LPS induced relatively less apoptosis. Apoptotic gene expressions revealed more pronounced increase in the cerulein group than those in cerulein plus LPS group. The expressions of GRP78 and downstream molecules were different in two cell models. GRP78 expression was down-regulated in cerulein group and upregulated in cerulein plus LPS group. CONCLUSIONS: GRP78 expression was associated with apoptosis and the severity of cerulein-induced pancreatic inflammation, indicating that GRP78 might prevent apoptosis in pancreatic acinar cells thereby deteriorating the severity of AP.

[Establishment of pancreatic acinar cell line AR42J with stable knockdown of GRP78].

OBJECTIVE: To design and construct a lentiviral vector containing shRNA against rat glucose-regulated protein 78 gene (GRP78), and to establish rat pancreatic acinar cell line with stable knockdown of GRP78 expression. METHODS: Constructed three plasmid expression vectors coding shRNA against GRP78, and converted them into lentiviral particles using three plasmid package systems. Then, AR42J cells were transduced with produced lentiviral particles. The green fluorescent protein (GFP) positive cells were selected by fluorescence-activated cell sorting (FACS), the GRP78 gene mRNA and protein expression were detected by real-time PCR and Western blot. RESULTS: The DNA sequencing showed that the lentiviral vectors containing shRNA against GRP78 gene were constructed correctly. After the transduction, highly efficient transduction (> 85%) of lentivirus in AR42J cells was observed by fluorescent microscopy and FACS. Quantitative real-time PCR showed that GRP78 mRNA expression in AR42J cells was suppressed by LVshGRP78-1, LVshGRP78-2 and LVshGRP78-3 lentivirus about 69.4% +/- 1.42%, 74.7% +/- 1.69% and 86.6% +/- 1.73% as compared with that of the untreated cells (P < 0.05), while LV-Non Target had no significant effect on the GRP78 mRNA level (P > 0.05). Western blot showed that the suppressed effect of LVshGRP78 lentivirus on GRP78 protein was consistent with GRP78 mRNA. CONCLUSION: The results demonstrated that lentiviral vectors containing the shRNA against GRP78 gene were successfully constructed, which could stably knock down the GRP78 expression in AR42J cells. This study will provide a new cell model for further study of the role of GRP78 in the pathogenesis of acute pancreatitis.

[Establishment of pancreatic ductal cell lines with stably silencing of MyD88 mediated by lentivirus].

OBJECTIVE: To design and construct a lentiviral vector containing shRNA against rat myeloid differentiation protein 88 gene (MyD88), and to establish rat pancreatic ductal cell line with stable knockdown of MyD88 expression. METHODS: Constructed two plasmid expression vectors coding shRNA against MyD88 and converted them into lentiviral particles using three-plamid package system, named as Lenti-sh MyD88-1 and LentishMyD88-2. Rat pancreatic ductal cell, ARIP were divided into untreated group, Lenti-Non Target group, LentishMyD88-1 and LentishMyD88-2 treated groups, and transduced with corresponding lentiviral particles. The GFP positive cells were selected by fluorescence-activated cell sorting and puromycin, the MyD88 gene silencing efficiency was detected by real-time RT-PCR. RESULTS: After the transduction, we observed highly efficient transduction (reach to 100%) of lentivirus in ARIP cells by fluorescent microscopy and FACS. Quantitative RT-PCR showed that Lenti-shMyD88-1 reduced MyD88 mRNA expression by about 82.73% +/- 1.203% in ARIP cells, and LentishMyD88-2, reduced 75.56% +/- 1.176% as compared with that of the untreated cells (P < 0.05). CONCLUSION: The results demonstrated that lentivector containing the short hairpin RNA expression cassette specifically targeting MyD88 (pLVshMyD88-1,-2) were successfully constructed, which could stably knock down the MyD88 expression in ARIP cells. This study finally provided a new and stable cell model for the study of MyD88's function in acute pancreatitis.

Age-related differences of genetic susceptibility to patients with acute lymphoblastic leukemia.

Inherited predispositions to acute lymphoblastic leukemia have been well investigated in pediatric patients, but studies on adults, particularly Chinese patients, are limited. In this study, we conducted a genome-wide association study in 466 all-age Chinese patients with Acute lymphoblastic leukemia (ALL) and 1,466 non-ALL controls to estimate the impact of age on ALL susceptibility in the Chinese population. Among the 17 reported loci, 8 have been validated in pediatric and 1 in adult patients. The strongest association signal was identified at ARID5B locus and gradually decreased with age, while the signal at GATA3 exhibited the opposite trend and significantly impact on adult patients. With genome-wide approaches, germline variants at 2q14.3 rank as the top inherited predisposition to adult patients (e.g., rs73956024, P = 4.3 × 10-5) and separate the genetic risk of pediatric vs. adult patients (P = 3.6 × 10-6), whereas variants at 15q25.3 (e.g., rs11638062) have a similar impact on patients in different age groups (overall P = 2.9 × 10-7). Our analysis highlights the impact of age on genetic susceptibility to ALL in Chinese patients.

miR-124 Intensified Oxaliplatin-Based Chemotherapy by Targeting CAPN2 in Colorectal Cancer.

Our previous study demonstrated that miR-124 was downregulated in colorectal cancer (CRC) compared with normal mucosa, and the downregulated expression of miR-124 was an independent prognostic factor in CRC patients. However, the function of miR-124 in CRC patients treated with chemotherapy is currently unclear. The aim of this study was to determine the miR-124 expression and its regulative role in oxaliplatin (L-OHP)-based chemotherapy of CRC patients. We observed that low miR-124 expression was correlated with worse overall survival (OS) in the 220 patients who received postoperative chemotherapy of 5-fluorouracil [5-FU]+leucovorin+L-OHP (FOLFOX) or capecitabine+L-OHP (XELOX). miR-124 overexpression promoted L-OHP-induced, but not 5-FU-induced, cytotoxicity and apoptosis in HT29 and SW480 cells. CAPN2 was a direct target of miR-124, and its protein expression was reduced by forced expression of miR-124. miR-124 inhibited tumorigenesis and promoted OS of mice bearing xenograft tumors, especially upon L-OHP treatment. miR-124 also promoted L-OHP-induced apoptosis and restrained CAPN2 protein expression in xenograft tumors. Our results suggest that miR-124 could be considered as both a predictor of L-OHP-based chemotherapy for personalized treatment and a therapeutic target for CRC.

[Mixed enzyme applied to develop the method on BAlb/c mouse Kupffer cell isolated and cultured in vitro].

OBJECTIVE: To research the reliable method for the isolation and culture of Kupffer cell in BALB/c mouse by mixed enzyme. METHODS: Kupffer cells were isolated from liver by in situ perfusion and digestion with 0.1% IV collagenase, 0.2% pronase and 0.01% Dnase I, and by percoll density gradient centrifugation. Kupffer cells were identified by fluorescence microscope, immunohistochemistry and cell endocytosis effect. RESULTS: Kupffer cells were isolated successfully with high purity, the yield of (2-3) 10(6)/per mouse liver and the identification that 0.4% trypan blue indicated that the cells survival rate and purity were more than 96% and more than 92% respectively. The shape of Kupffer cell appeared to be multiplicity, irregularity, polygon and multiangular. Kupffer cells showed lysozyme positive by immunohistochemistry staining. And particles of India ink were found in cytoplasm. CONCLUSION: Here described technique for isolation and culture of Kupffer cells is simple and reliable, and can be used for preparing Kupffer cells with high yield, activity and purity.

Deletion Of XIAP reduces the severity of acute pancreatitis via regulation of cell death and nuclear factor-κB activity.

Severe acute pancreatitis (SAP) still remains a clinical challenge, not only for its high mortality but the uncontrolled inflammatory progression from acute pancreatitis (AP) to SAP. Cell death, including apoptosis and necrosis are critical pathology of AP, since the severity of pancreatitis correlates directly with necrosis and inversely with apoptosis Therefore, regulation of cell death from necrosis to apoptosis may have practicably therapeutic value. X-linked inhibitor of apoptosis protein (XIAP) is the best characterized member of the inhibitor of apoptosis proteins (IAP) family, but its function in AP remains unclear. In the present study, we investigated the potential role of XIAP in regulation of cell death and inflammation during acute pancreatitis. The in vivo pancreatitis model was induced by the administration of cerulein with or without lipopolysaccharide (LPS) or by the administration of l-arginine in wild-type or XIAP-deficient mice, and ex vivo model was induced by the administration of cerulein+LPS in AR42J cell line following XIAP inhibition. The severity of acute pancreatitis was determined by serum amylase activity and histological grading. XIAP deletion on cell apoptosis, necrosis and inflammatory response were examined. Caspases activities, nuclear factor-κB (NF-κB) activation and receptor-interacting protein kinase1 (RIP1) degradation were assessed by western blot. Deletion of XIAP resulted in the reduction of amylase activity, decrease of NF-κB activation and less release of TNF-α and IL-6, together with increased caspases activities and RIP1 degradation, leading to enhanced apoptosis and reduced necrosis in pancreatic acinar cells and ameliorated the severity of acute pancreatitis. Our results indicate that deletion of XIAP switches cell death away from necrosis to apoptosis and decreases the inflammatory response, effectively attenuating the severity of AP/SAP. The critical role of XIAP in cell death and inflammation suggests that inhibition of XIAP represents a potential therapeutic strategy for the treatment of acute pancreatitis.

Knockdown of Myeloid Differentiation Factor 88 Attenuates Lipopolysaccharide-Induced Inflammatory Response in Pancreatic Ductal Cells.

OBJECTIVES: The aim of the study was to explore the potential role of myeloid differentiation factor 88 (MyD88), which acts as an adaptor in the TLR4 signalling pathway, in immune responses of the pancreatic duct during acute pancreatitis. METHODS: Primary cultures of pancreatic duct epithelial cells from Wistar rats and cultures of the pancreatic ductal ARIP cell line were treated with lipopolysaccharide (LPS), and expression of toll-like receptor 4 mRNA was determined using real-time PCR, expression of MyD88 protein using Western blot, and levels of inflammatory cytokines using enzyme-linked immunosorbent assay. These experiments were repeated using ARIP cells in which MyD88 expression was stably knocked down. RESULTS: Toll-like receptor 4 and MyD88 expression were similar between pancreatic duct epithelial cells and ARIP cells after LPS stimulation. Myeloid differentiation factor 88 knockdown led to significantly lower levels of inflammatory cytokines after LPS induction in ARIP cells. CONCLUSIONS: Myeloid differentiation factor 88 knockdown attenuates LPS-induced inflammatory responses in pancreatic ductal cells, suggesting that the MyD88 pathway plays a critical role in their immune defense activity.

Knockdown of GRP78 promotes apoptosis in pancreatic acinar cells and attenuates the severity of cerulein and LPS induced pancreatic inflammation.

Acute pancreatitis (AP) is a potentially lethal disease characterized by inflammation and parenchymal cell death; also, the severity of AP correlates directly with necrosis and inversely with apoptosis. However, mechanisms of regulating cell death in AP remain unclear. The endoplasmic reticulum (ER) chaperone protein GRP78 has anti-apoptotic properties, in addition to modulating ER stress responses. This study used RNA interference (RNAi) approach to investigate the potential role of GRP78 in regulating apoptosis during AP. In vitro models of AP were successfully developed by treating AR42J cells with cerulein or cerulein plus lipoplysaccharide (LPS). There was more pancreatic inflammation and less apoptosis with the cerulein plus LPS treatment. Furthermore, knockdown of GRP78 expression markedly promoted apoptosis and reduced necrosis in pancreatic acinar cells. This was accomplished by enhancing the activation of caspases and inhibiting the activity of X-linked inhibitor of apoptosis protein (XIAP), as well as a receptor interacting protein kinase-1(RIPK1), which is a key mediator of necrosis. This attenuated the severity of pancreatic inflammation, especially after cerulein plus LPS treatment. In conclusion, these findings indicate that GRP78 plays an anti-apoptotic role in regulating the cell death response during AP. Therefore, GRP78 is a potential therapeutic target for AP.

Knockdown of MMP-7 inhibits cell proliferation and enhances sensitivity to 5-Fluorouracil and X-ray irradiation in colon cancer cells.

The role of matrix metalloproteinase-7 (MMP-7) in the pathogenesis of colon cancer is not understood thoroughly. Previous studies from our group have shown that the expression levels of MMP-7 were highly elevated in colorectal cancer patient specimens and were correlated with Dukes Staging, histological differentiation grade and CEA level. The goal of this study was to investigate the cellular impact of MMP-7 in colon cancer. In this study, we used the SW480 colon cancer cell lines of MMP-7 knockdown by lentivirus-mediated RNA interference as a model system to investigate the impact of MMP-7 on cell proliferation and sensitivity to 5-Fluorouracil (5-FU) and X-ray irradiation (IR). Cell proliferation and sensitivity to 5-FU and IR were measured by MTT assay and colony formation assay. Cell cycle was evaluated by flow cytometry. We showed that the down regulation of MMP-7 inhibits colon cancer cell proliferation and sensitizes tumour cells to 5-FU and IR (P < 0.05). Decreased MMP-7 expression in SW480 cells by RNA interference triggered cell cycle arrest at G1 phase (P < 0.05). Down regulation of MMP-7 may inhibit the cell proliferation of colon cancer cells and increase tumour cells sensitivity to radiotherapy and chemotherapy. RNAi-mediated silencing of MMP-7 may represent a powerful therapeutic approach for controlling human colorectal cancer growth.

The prognostic significance of peroxisome proliferator-activated receptor ß expression in the vascular endothelial cells of colorectal cancer.

OBJECTIVE: Currently, little is known regarding the role of peroxisome proliferator-activated receptor-ß (PPAR ß) in the vascular endothelial cells (VECs) of colorectal cancers (CRCs). The aim of this study was to investigate the relationship of PPAR ß expression in the VECs of CRCs in terms of the prognosis and clinicopathological features of CRC patients. DESIGN: The expression and localization of PPAR ß in the primary cancers and the matched normal mucosal samples of 141 Swedish CRC patients were analyzed in terms of its correlation with clinicopathological features and the expression of angiogenesis-related genes. This study also included 92 Chinese CRC patients. RESULTS: PPAR ß was predominantly localized in the cytoplasm and was significantly downregulated in the VECs of CRC compared to that of the normal mucosa. The low expression levels of PPAR ß in the VECs of CRC were statistically correlated with enhanced differentiation, early staging and favorable overall survival and were associated with the increased expression of VEGF and D2-40. The patients exhibiting elevated expression of PPAR ß in CRC cells but reduced expression in VECs exhibited more favorable survival compared with the other patients, whereas the patients with reduced expression of PPAR ß in CRC cells but increased expression in VECs exhibited less favorable prognosis. CONCLUSIONS: PPAR ß might play a tumor suppressor role in CRC cells in contrast to a tumor promoter role in the VECs of CRCs.

[Clinicopathological significance of microRNA-21 and miR-125 expression in colorectal cancer].

OBJECTIVE: To investigate the expression of microRNA(miR)-21 and miR-125 in colorectal cancer (CRC) and its relationship with clinicopathological features. METHODS: Quantitative real-time PCR was applied to examine the expression of miR-21 and miR-125 in 100 primary CRC specimens which were diagnosed and operated in West China Hospital between 2006 and 2007, in comparison with the corresponding normal mucosa specimens. The relationship between the expression of miRNAs and clinicopathological features was analyzed. RESULTS: The expression of miR-21 in CRC was up-regulated by 2.3 times compared to normal mucosa (P =0.025), while the expression of miR-125 was down-regulated by 3.3 times in comparison with normal mucosa (P =0.005). Furthermore, the expression of miR-21 was related to TNM stage (P =0.028) and local invasion (P =0.023). On the other hand, no significant relationship was found between the expression of miR-125 and clinicopathological features (P >0.05). CONCLUSION: The over-expression of miR-21 may play a role in the development and progression of CRC, while miR-125 may not be related to the pathogenesis of CRC.

An improved primary culture system of pancreatic duct epithelial cells from Wistar rats.

Pancreatic duct epithelial cells (PDEC) are involved in most common pancreatic diseases. Primary cultivation of PDEC is a prerequisite for in vitro studies, in which in vivo situations can be simulated and molecular mechanisms investigated better than in cultured cell lines. However, some problems still exist regarding rat PDEC primary cultivation. In this study, an improved primary culture system of rat PDEC is presented. Some modifications, especially regarding specimen chosen, digestive control and epithelium purification, were made to simplify the procedure, increase cell yield, and improve epithelium purification. Cultures were identified as PDEC by morphological characteristics, reverse transcription-polymerase chain reaction and immunocytochemistry staining with cytokeratin 19. In addition, growth characteristics of rat PDEC are described in detail. This improved technique, which is more efficient and cost-effective, will be useful for in vitro pancreatic studies.