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Background:Recent studies have shown that long non-coding RNAs(lncRNAs)play important roles in carcinogenesis and cancer biology and the related context has attracted more and more attentions. PVT1,which encodes a lncRNA,is reported to be up-regulated and exhibit pro-oncogenic activity in a wide variety of human cancers. Aims:To investigate the expression of PVT1 in human pancreatic cancer cells and its effect on proliferation and apoptosis of HPAF-Ⅱ cells. Methods:One target siRNA against PVT1 was synthesized and transfected into HPAF-Ⅱ cells by using lipofactamine technique. PVT1 mRNA expression was detected by real-time PCR;capability of cell proliferation was examined by MTS and colony formation assays;cell cycle progression and apoptosis were measured by flow cytometry;and Western blotting was performed to determine the expressions of apoptosis-related proteins and proto-oncogene protein c-Myc. Results:The mRNA expression of PVT1 in several human pancreatic cancer cell lines,especially HPAF-Ⅱ cells was significantly higher than that in H6c7,a human immortalization normal pancreatic ductal epithelial cell line. Compared with HPAF-Ⅱ cells transfected with negative control siRNA or without transfection,silencing of PVT1 by siRNA-PVT1 resulted in remarkable reduction in cell proliferation,cell cycle G1 phase arrest,and notable apoptosis;meanwhile,the expressions of apoptosis-related proteins(cleaved-caspase-3 and cleaved-PARP)were up-regulated,the ratio for Bcl-2 / Bax was decreased,and the expression of c-Myc protein was down-regulated. Conclusions:LncRNA-PVT1 is highly expressed in human pancreatic cancer cell line HPAF-Ⅱ. It may affect the proliferation and apoptosis of HPAF-Ⅱ cells partially through regulating c-Myc expression.
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Plasmacytoma variant translocation1 (PVT1) is a very important long nocoding RNA,which located at chromosome 8q24.21 in human beings.Aberrant expression and polymorphism of PVT1 was closely associated with various kinds of cancers such as malignant lymphoma,breast cancer,colorectal cancer,pancreatic cancer,and affected survival and prognosis of cancer patients.This mainly attribute to its interactin with myc,miRNAs and other proteins,and also gene polymorphism.Further study of PVT1 is expected to provide a new target for the diagnosis and treatment of cancer.
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Objective To investigate the effects on self-renewal of pancreatic cancer stem cells by inhibiting hedgehog signaling pathway through cyclopamine. Methods PANC1 stem cells, PANC1 adherent cells and immortalized pancreatic ductal epithelial H6C7 cells were treated with 0.5, 1, 2, 5, 10 mol/L of cyclopamine for 24, 48, 72 h. The expression of Smo mRNA and Gli1 mRNA were detected by real-time PCR.Cell growth viability was measured by CCK 8. Cell cycle and apoptosis were determined by flow cytometry.Results Seventy-two hours after cyclopamine treatment, the Smo mRNA expressions of PANC1 stem cells,PANC1 adherent cells and H6C7 cells were 1,0.83 and 2.61; the expressions of Gli mRNA were 57.27,26.35,1; the inhibitory rates were ( 37.85 ± 13.69 ) %, ( 8.53 ± 4.43 ) %, (43.55 ± 28.98 ) %. Compared with PANC1, the expressions of Smo mRNA, Gli1 mRNA and the inhibitory rate of PANC1 stem cells significantly increased ( P ＜ 0.05 ). The proportion of G1 stage of PANC1 stem cells significantly decreased from (67.41 ±6.35)% to (36.53 ±6.03)% (P ＜0.05), and the apoptosis decreased from (10.95 ±5.68) % to ( 5.73 ± 1.42 ) % ( P ＞ 0.05 ). The proportion of G1 stage of PANC1 cells significantly decreased from ( 67.64 ± 6.88 ) % to ( 53.13 ± 1.10 ) % ( P ＜ 0.05 ); the apoptosis decreased from ( 12.08 ±4.12)% to (5.66 ± 1.33)% (P ＞0.05). While both the proportion of G1 stage and apoptosis of H6C7 cells was not significantly different. Conclusions Cyclopamine can inhibit the proliferation of PANC1 stem cells via blocking hedgehog signal pathway, and the mechanism may not be associated with cell apoptosis.
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Objective To investigate the prevalence and the clinical features of pancreatic cancer pain in a Chinese patient population.Methods The study was carried out in 415 cages of pancreatic cancer which were admitted to the First Municipal people's Hospital of Guangzhou Medical college and the Second Affiliated Hospital of Sun Yat-sen University from 1999 to 2007.The prevalence,clinical features of pancreatic cancer pain and its correlations with the cancer site and the clinical staging were analyzed.Results Of the 415 patients.the prevalence of pain wag 65.1%and 60.5%of all the patients presented pain as the initial symptom;the incidence of pain in pancreatic body/tail cancer patients was 80.7%.while it was 71.4%in total pancreatic cancer patients.and the incidence was 58.2%in pancreatic head cancer patients;the incidence between pancreatic body/tail cancer and pancreatic head cancer patients was statistically different (P＜0.05).The incidence of pain in patients with stage Ⅰ,Ⅱ,Ⅲ,and Ⅳ was 28.6%,58.1%,66.2%and 78.6%.and the difference was statistically significant(P＜0.01).The incidence of moderate to severe degree of pain in patients with stage Ⅰ,Ⅱ,Ⅲ,and Ⅳ was 18.8%,44.4%,53.1%and 68.2%,and the differenee was statistically significant(P＜0.01).Conclusions Pain was very common in patients with advanced pancreatic cancer.The incidence and severity of pain increased with the progression of pancreatic cancer.
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Objective To establish the method of suspension culture for stem cells from human pancreatic cancer cell line PANC1.Methods PANC1 cells were cultured in serum-free medium under floating-culture system.Tumor cell spheres were observed by optical microscope.Expression of CD133 and cell cycle were detected by flow cytometry.Cancer stem cells were induced to differentiate with 10%FBS,and expression of CK18,was evaluated with immunofluorescence microscope.Spheres cells were injected into the subcutaneous space of NOD/SCID rat and tumor formation was monitored weekly.Results PANC1 cells could form the stem cells spheres,and the rate of sphere formation was stable between 4%0 and 5%0 after 20 passages in vitro.The expression of CD133(5.91±0.7%)and proportion of G0/G1 phase cell(80.99±2.60%)was significantly increased in spheres cells compared with parental PANC1 cells(1.44±0.52%and 69.01±5.03%),and the difference was statistically significant(P＜0.05).When these spheres cells were cultured in media with serum,these cells gradually returned to the status of parental cells and expressed CK18,2×103 sphere cells injection could initiate tumor fornmtion in NOD/SCID rat.Conclusions Tumor spheres stem cellscould be generated under serum-free floating-culture system.The sphere cells possessed the capacities of self renew,difierentiation,and tumorigenic potential.
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Objective To compare the clinical efficacy of gemcitabine arterial infusion chemotherapy with intravenous chemotherapy in the management of patients with advanced pancreatic cancer and to evaluate the efficacy and safety of gemcitabine arterial infusion chemotherapy. Methods 43 patients with advanced pancreatic cancer were included in this study, of whom 21 patients received arterial infusion chemotherapy (Group A) and the other 22 were treated by intravenous chemotherapy (Group B), gemcitabine combined with 5-FU chemotherapy was administrated in both groups. The main outcomes were clinical benefit response (CBR), tumor response rate and toxicity. Results Compared with Group B, there was a significant improvement of CBR in group A (81% vs 50%, P =0.033) ; there was also significant improvement of pain control in group A (76.2% vs 45.5%, P =0.039). There was no significant difference in the tumor response rate between two groups (33.3% vs 22.7%, P =0.498). No significant increase of side effects was observed in both groups. Conclusions In the management of advanced pancreatic cancer, the arterial infusion method may be more favorable than intravenous approach in improving clinical benefits with mild toxicity and well tolerability.
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Objective To isolate and identify side population (SP) cells like cancer stem cell from human pancreatic cancer cell line SW1990, for the purpose of further evaluation of their biological characteristics. Methods Cell suspension was stained with Hoechst 33342 and PI. Then SP cells were analyzed in the fluorescence activated cell sorter. Cell growth viability was measured by MTT. Stem cell marker CD133 was determined by flow cytometry. Cloning forming efficiency was determined by cloning plating. Expression of ABCG2 protein was detected by Western blot analysis. Results The proportion of SP cells was 2.7%, however it could be completely blocked by verapamil. 9 days later, the value of A492 of SP cells was 2.1, the cloning forming efficiency was (38.7 ± 6.8) % , the positive rate of CD133 was 69.63%, which were significantly higher than cells 0. 5, ( 15.5 ± 2.8)%, 16.71% of corresponding non-SP( P <0.05). The expression of ABCG2 in SP cells was significantly higher than that in non-SP cells. Conclusions SP cells existed in human pancreatic cancer cells SW1990.
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The hypothesis of tumor stem cells believes that a small proportion of cells which have the stemness property reside in tumor. This population is the cause of tumor formation, growth, metastasis and relapse. Only the therapy targeting this population could make tumors curable. At present, most anti-cancer protocols only kill the majority of differentiated tumor cells and hardly affect the tumor stem cells. That is why most of the therapies do not achieve good results. Disrupting the pathways and niche which regulate the tumor stem cells’ self-renewal, or inducing the tumor stem cells’ differentiation, or targeting the surface markers which distinguish the tumor stem cells from normal stem cells are all probable strategies.
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AIM: To elucidate the pattern of 5-fluorocytosine(5-FC) induced apoptosis and its role in gene therapy for human pancreatic cancer. METHODS: The human pancreatic cancer SW1990 cells(CEA-producing) were infected with recombinant adenoviruses(Adex1CEA-prCD or Adex1CEA-prZ).Cytosine deaminase(CD) expression was examind by western blot. Apoptosis induced by 5-FC in human pancreatic cancer SW1990 cells genetically modified to express cytosine deaminase was investigated by applying electron microscopy, DNA electrophoresis and flow cytometry analysis techniques. RESULTS: The SW1990 cells infected with Adex1 CEA-prCD were treated with 5-FC at 100 ?mol?L -1 for 48 h, cell apoptosis occurred. Typical apoptosis morphological feature appeared and DNA ladder could be demonstrated on DNA electrophoresis. Apoptosis peak was also showed by flow cytometry. Apoptotic cells accounted for 34.6% of the cell population. Cells in G 1, S and G 2/M phase of cell cycle were 64%, 11% and 7%, respectively. CONCLUSION: The apoptosis induced by 5-FC may be a primary mechanism in CD gene therapy for pancreatic cancer.
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AIM: To investigate the expression of MAT1 protein in pancreatic cancers and the relationship between MAT1 and clinicopathological features of pancreatic cancers. METHODS: 94 surgical specimens, including 70 pancreatic cancers, 10 pancreatic benign tumors, 14 chronic pancreatitis and 10 autopsy normal pancreas tissues, were analyzed immunohistochemically, and then MAT1 expression and clinicopathological features were compared. RESULTS: MAT1 was expressed mainly in the cancer cells,and also in the fibroblasts, where it was localized within the cytoplasm and nuclear envelope. MAT1 expression was found in 75.7% (53/70) of the cancers, but not detected or weakly expressed in control tissues. There was a significant difference in expression of MAT1 among the above four tissues (P