【Abstract】 Objective To investigate the expression and significance of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptors in pancreatic cancer. Methods Thirty-two samples of pancreatic cancer tissue were collected from year 2002 to 2004. All of them were verified by histopathology and there were 9 cases of well-differentiated, 12 of moderately differentiated, and 11 of poorly differentiated, in which 12 cases were in the stage of Ⅰor Ⅱand 20 in the stage of Ⅲ or Ⅳ according to the TNM staging method. Eighteen normal pancreatic tissues were used as control group. The expressions of TRAIL receptors (death receptor 4, death receptor 5, decoy receptor 4 and decoy receptor 5) mRNA were assayed by semi-quantitive reverse transcription polymerase chain reaction (RT-PCR) in the pancreatic cancer tissues and the normal pancreatic tissues. Results The expressions of death receptor 4 (DR4) and death receptor 5 (DR5) were detected in all the pancreatic cancer tissues and the normal pancreatic tissues and the levels of DR4 and DR5 were significantly higher than those of the normal pancreatic tissues (P＜0.01). Decoy receptor 1 (DcR1) and decoy receptor 2 (DcR2) were also expressed in normal pancreatic tissues, whereas DcR1 and DcR2 were only expressed in 18 and 20 pancreatic cancer tissues, respectively. However, there were no significant difference of the expression of DcR1 and DcR2 between the pancreatic cancer tissues and the normal pancreatic tissues （Pgt;0.05）. The expression level of DR5 in pancreatic cancer tissue was correlated with tumor differentiation and clinical stage, and the levels in stage Ⅲ and stage Ⅳwere significantly lower than those of stageⅠand stageⅡ(P＜0.05). The expressions of DR4, DcR1 and DcR2 were not correlated with tumor differentiation and clinical stage (Pgt;0.05). Conclusion ①The expression of TRAIL receptors in pancreatic cancer tissues is prevalent, but the types of receptors expressed in different tissues were also different. High expression of death receptors may play an important role in TRAIL recptors regulated pancreatic cancer apoptosis. ②The expression of DR5 is correlated with the differentiation degree of pancreatic cancer cell and clinical stage of tumor. The expressions of DR4, DcR1 and DcR2 should not be considered as related indexes of differentiation degree or clinical stage of pancreatic cancer.
ObjectiveTo study the expression of apoptosissuppressing gene (bcl2) and apoptosispromoting gene (bax) in colorectal cancerous tissue and transitional mucosas. MethodsColorectal cancerous tissue, transitional mucosas (3 cm from the cancerous tissue) and normal tissue were taken respectively in thirtyone cases. Immunohistochemical technique SP method was used to detect the expression in those tissues. ResultsThe positive expression rate of bcl2 protein in cancerous tissue and transitional mucosa were 64.5%and 60.0% respectively and significantly higher than that in normal tissue (P＜0.05). The positive expression rate of bcl2 protein in normal tissue was 35.0%. The positive expression rate of bax protein in cancerous tissue and transitional mucosa were 45.2%and 45.0% respectively and significantly lower than that in normal mucosa (P＜0.05). The positive expression rate of bax protein in normal tissue was 60.0%. There was no obvious difference in the positive rate of bax and bcl2 protein between cancerous tissue and transitional mucosa (Pgt;0.05). The expression rate of bax and bcl2 protein in colorectal cancer was irrelative to clinical pathological gradation and clinical stage (Pgt;0.05). ConclusionThere is over expression of bcl2 protein and low expression of bax protein in colorectal cancer and transitional mucosa. bcl2 protein and bax protein can affect the generation of colorectal cancer by participating in the regulation of apoptosis. But it is irrelative to clinical pathological gradation and clinical stage. Transitional mucosas should be viewed as precancerous lesion and resected during operation.
Objective To investigate the mechanism of the resistance of pancreatic cancer cells to tumor necrosis factor related apoptosis inducing ligand (TRAIL)mediated apoptosis. MethodsThe expression of TRAIL receptor-4 (TRAIL-R4) in normal pancreas tissue and pancreatic cancer was analyzed by using Northern blotting, Western blotting and immunohistochemistry.ResultsTRAIL-R4 mRNA and protein were expressed at moderate to high levels in human pancreatic cancer, but demonstrated weak to negative in the normal pancreas. Moreover, pancreatic cancer cells showed b TRAIL-R4 immunostaining throughout the tumor mass. Conclusion TRAIL-R4 levels are significantly different in pancreatic cancer in comparison to the normal pancreas. These findings give new insights into the resistance mechanisms of pancreatic cancer cells towards TRAILmediated apoptosis.
Objective To investigate the effect of ursolic acid on the proliferation and apoptosis of human osteosarcoma cell line U2-OS and analyze its mechanism. Methods Human osteosarcoma cell line U2-OS was divided into 4 groups, which was cultured with ursolic acid of 0, 10, 20, and 40 μmol/L, respectively. At 0, 24, 48, and 72 hours after being cultured, the cell proliferation ability was detected by cell counting kit 8 (CCK-8). At 48 hours, the effects of ursolic acid on cell cycle and apoptosis of U2-OS cells were measured by flow cytometry. Besides, the expressions of cyclin D1 and Caspase-3 were detected by real-time fluorescent quantitative PCR and Western blot. Results CCK-8 tests showed that the absorbance (A) value of each group was not significant at 0 and 24 hours (P>0.05); but the differences between groups were significant at 48 and 72 hours (P<0.05). Flow cytometry results showed that, with the ursolic acid concentration increasing, the G1 phase of U2-OS cells increased, the S phase and G2/M phase decreased, and cell apoptosis rate increased gradually. There were significant differences between groups (P<0.05). Compared with the 0 μmol/L group, the relative expressions of cyclin D1 mRNA and protein in 10, 20, and 40 μmol/L groups significantly decreased (P<0.05); whereas, there was no significant difference in relative expression of Caspase-3 mRNA between groups (P>0.05). However, with the ursolic acid concentration increasing, the relative expressions of pro-Caspase-3 protein decreased and the relative expressions of activated Caspase-3 increased; there were significant differences between groups (P<0.05). Conclusion Ursolic acid can effectively inhibit the proliferation of osteosarcoma cell line U2-OS, induce the down-regulation of cyclin D1 expression leading to G0/G1 phase arrest, increase the activation of Caspase-3 and promote cell apoptosis.
ObjectiveTo observe apoptosis and proliferation of choledochus wall epithelial cell and fibrocyte, to understand the effects of apoptosis and proliferation on choledochal cyst development.MethodsThirty two cases of cystic dilatation,35 cases of cylindrical dilatation，and 25 cases of cholangiectasis caused by choledocholith were collected. All specimens were offered by department of hepatobiliarypediatric surgery. The apoptosis related index (bcl2 and bax) and cell proliferation index (PCNA) were detected by the immunohistochemical technique; Apoptosis was detected by TUNEL method. ResultsThere was serious mucosal epithelial cell damage in cystic dilatation group. In cylindrical dilatation group there was a damage similar to that of the cystis dilatation group, but the damage was not serious. In control group there was little damage in the duct wall, but there was a low positive rate of apoptosis of 〔epithelium cell (2.74±1.00)% and fibroblast (2.95±0.87）%〕, and a low bcl2 and bax’s expression rate, and a high PCNA’s expression rate 〔epithelium cell (3.74±1.00)%, fibroblast (3.71±1.77)%〕. There was no obvious difference between cylindrical dilatation group and cystic dilatation group (Pgt;0.05): the PCNA’s expression rate was low 〔(0.99±0.51)% and (0.90±0.38)% respectively〕, the bax expression rate was high in remaining epithelial cell, and the positive rate of bax was apparently higher than that of bcl2 (P＜0.05), the positive rate of the apoptosis cell was high 〔(13.94±4.77)%, (7.51±3.46)%〕; the expression rate PCNA were high 〔(9.91±2.91)%,(9.70±3.18)%〕, and expression rate of bax’s was low in the fibre tissue, the positive rate of bcl2 was markedly higher than that of bax, and the positive rate of the apoptosis cell was low 〔(3.74±2.12)%,(4.46±2.41)%〕. There were no marked difference between the two groups (Pgt;0.05). The expression of bcl2 and bax had marked difference both in cylindrical dilatation group and cystic dilatation group and as compared to control group (P＜0.05). ConclusionApoptosis has certain promoting effect in the course of choledochal cyst formation.
ObjectiveTo investigate the effects of dipyridamole (DP), one of the human equilibrative nucleoside transporters (hENTs) blockers, on 5-fluorouracil (5-FU) induced cell apoptosis and cell cycle changes of the pancreatic cancer Panc-1 cell line. MethodsPancreatic cancer cell line Panc-1 was divided into hENTs blocked group and hENTs unblocked group. The hENTs blocked group was further divided into two subgroups according to the DP concentration, 5 μmol/L DP group and 10 μmol/L DP group. Each group was incubated in culture medium with or without 1.5×106 ng/L 5-FU for 24 h. Cell apoptosis and cell cycle were detected by flow cytometry. Results①The apoptosis results of each group： Incubated in culture medium with 1.5×106 ng/L 5-FU for 24 h, the apoptosis rates of 5 μmol/L DP group and 10 μmol/L DP group were higer than those of hENTs unblocked group （Plt;0.05）, and which of 10 μmol/L DP group was higer than that of 5 μmol/L DP group (Plt;0.05). Incubated in culture medium without 5-FU for 24 h, there were no significant differences of the apoptosis rates among three groups (Pgt;0.05). ②The cell cycle results of each group: Incubated in culture medium with 1.5×106 ng/L 5-FU for 24 h, the percentages of S phase cells in the 5 μmol/L DP group and 10 μmol/L DP group were less than those of hENTs unblocked group (Plt;0.05). The percentage of S phase cell of 5 μmol/L DP group reduced to 87.09% and that of 10 μmol/L DP group reduced to 74.06% as compared with hENTs unblocked group. 5-FU had little influence on G2 phase (Pgt;0.05) except for the percentage of G2 phase cells in the 5 μmol/L DP group increased significantly (Plt;0.05) as compared with the hENTs unblocked group. Incubated in culture medium without 5-FU for 24 h, there were no significant differences of the cell cycles among three groups (Pgt;0.05). ConclusionsIn pancreatic cancer Panc-1 cell, DP could enhance the cytotoxicity of 5-FU by blocking hENTs. The enhanced cytotoxicity is related to elevation of 5-FU concentration in cells, and unrelated to DP itself.
Objective To investigate the inhibitory effect of survivin antisense oligonucleotides (ASODN) on proliferation of pancreatic cancer cells PANC-1. Methods The ASODN and sense oligodeoxynucleotides (SODN) were complementary to survivin sequences. FAM-marked ASODN was transfected into PANC-1 cells mediated by positive ion liposome as ASODN group. Blank control group (normal cells), negative control group (normal medium)， and SODN group were established for comparison. The transfection efficiency was detected by flow cytometry (FCM) after transfection; MTT assay was used to detect cytotoxicity; Cell morphological changes were examined by transmission electron microscopy; The cell cycle and apoptotic rate were analyzed by FCM; Immunohistochemical staining techniques were used, and the expressions of survivin were observed under light microscopy, examined and analysed by computer image. Results ①The transfection efficiency was 31.9%, 37.4%, 41.4%, 52.6%, 24.2%, 11.4%, 16.1%, and 15.5% when the transfecting concentration of ASODN was 50, 100, 150, 200, 250, 400, 600, and 800 nmol/L, respectively; The transfection efficiency was 12.0%, 50.8%, and 11.2% when the inoculated cells was 2×104/well, 2×105/well, and 2×106/well, respectively; The transfection efficiency was 58.8%, 34.0%, and 23.6% when 2 μl, 3 μl, and 4 μl liposome was used during transfection, respectively. ②Cell gap was oversize, morphous was round, adherent cells were less after transfection under fluorescence microscope. ③The inhibition rate in the ASODN group was higher than that in each control group (Plt;0.05) on 24, 36, 48 h after treating by survivin ASODN, which increased as time prolonged (Plt;0.05). ④The apoptosis showed a ladder-shaped line in the ASODN group. ⑤Apoptotic morphology was demonstrated in the ASODN group, such as apoptotic cells with nuclear chromatin highly concentrated, crescent nuclear staining aggregated by the side nuclear membrane, nucleolus disappeared by AO and EB stains. ⑥The apoptotic rate 〔（38.1±3.4）%〕 in the ASODN group was higher than that in the SODN group 〔（4.16±1.7）%〕, Plt;0.05. ⑦G2/M cell cycle arrested in the ASODN group. ⑧After transfection, the expression of survivin protein in the ASODN group was significantly lower than that of each control group (Plt;0.05). Conclusions The optimal transfection conditions are as following: the cell count of 2×105/well, concentration of ASODN 200 nmol/L, and cationic liposome oligofectamine 2 μl, respectively. Survivin ASODN can inhibit the proliferation of pancreatic cancer cells and induce their apoptosis.
Objective To investigate the expressions of tumor necrosis factor related apoptosis inducing ligand （TRAIL） and its receptors (DR4, DcR1) in human rectal cancer tissues and normal rectal tissues. MethodsThe expressions of TRAIL and its receptors (DR4, DcR1) in 31 cases of human rectal cancer tissues and 20 cases of normal rectal tissues were detected by immunohistochemical staining. ResultsThe positive expression rates of TRAIL, DR4 and DcR1 （32.26%， 29.03%， 0） were lower than those of normal rectal tissues （55.00%， 70.00%， 65.00%）, the difference was statistically significant(P=0.015， P=0.000， P=0.000). There were no relation between the expressions of TRAIL, DR4 and DcR1 and clinicopathologic characteristics (Pgt;0.05). ConclusionThe expressions of TRAIL and its receptors (DR4, DcR1) in human rectal cancer tissues were lower than those of normal rectal tissues, which may suggest that the apoptotic effect induced by the interaction between TRAIL and its receptors has attenuated in human rectal cancer.
ObjectiveTo study the role of survivin gene in the research work of tumor. MethodsLiteratures about the molecular structure, function, mechanism,distribution of survivin gene and its role in the treatment of tumor were reviewed.ResultsSurvivin was a new member of inhibitor of apoptosis protein family, expressed in almost all the human tumors independent to the expression of bcl2. The expression of survivin was significantly correlated with the poor prognosis of tumor patients. Survivin inhibited the apoptosis of tumor cells via inhibiting the activity of caspase3, the effector molecule of the apoptosis signal transduction pathway. Inhibition of the expression of survivin gene could block its effect of inhibiting apoptosis and consequently get a therapeutic effect of tumors.ConclusionSurvivin is commonly expressed in human tumor tissues. It can be identified as an important prognostic parameter of poor outcome and a new therapeutic target in cancer.
Objective To explore the expression and significance of hypoxia-inducible factor 1α (HIF-1α) in endplate chondrocytes, and to study the relations between HIF-1α expression and endplate chondrocytes apoptosis. Methods Eight Sprague Dawley rats were selected to obtain the L1-5 intervertebral disc endplate; the endplate chondrocytes were isolated by enzyme digestion method, and the endplate chondrocytes at passage 3 were cultured under 20% O2 condition (group A), and under 0.5% O2 condition (group B). Cell morphology was observed by inverted phase contrast microscope and cell apoptosis was detected using flow cytometry after cultured for 24 hours; the mRNA expression of HIF-1α was detected by real-time fluorescent quantitative PCR, the protein expressions of HIF-1α, Bax, and Bcl-2 by Western blot. Gene clone technology to design and synthesize two siRNAs based on the sequence of HIF-1α mRNA. HIF-1α specific RNAi sequence compound was constructed and transfected into cells. The transfected endplate chondrocytes at passage 3 were cultured under 0.5% O2 condition in group C and group D (HIF-1α gene was silenced). After cultured for 24 hours, cells were observed via immunofluorescence staining of HIF-1α, and cell apoptosis was detected using flow cytometry. Meanwhile, the mRNA expressions of HIF-1α, collagen type II (COL II), Aggrecan, and SOX9 were detected by real-time fluorescent quantitative PCR, and the protein expressions of HIF-1α, Bax, and Bcl-2 by Western blot. Results At 24 hours after culture, small amount of vacuoles necrotic cells could be observed in group A and group B; there was no significant difference in apoptosis rate between groups A and B (t=1.026,P=0.471), and HIF-1α mRNA and protein expressions in group B were significantly higher than those in group A (t=22.672,P=0.015;t=18.396,P=0.013), but, there was no significant difference in protein expressions of Bax and Bcl-2 between groups A and B (t=0.594,P=0.781;t=1.251,P=0.342). The number of vacuolar necrosis cells in group D was significantly higher than that in group C, and HIF-1α positive cells were observed in group D. The apoptosis rate of group D was significantly higher than that of group C (t=27.143,P=0.002). The mRNA expressions of HIF-1α, COL II, Aggrecan, and SOX9 in group D were significantly lower than those in group C (t=21.097,P=0.015;t=34.829,P=0.002;t=18.673,P=0.022;t=31.949,P=0.007). The protein expressions of HIF-1α and Bcl-2 in group D were significantly lower than those in group C (t=37.648,P=0.006;t=16.729,P=0.036), but the protein expression of Bax in group D was significantly higher than that in group C (t=25.583,P=0.011). Conclusion HIF-1α mRNA expression is up-regulated under hypoxia condition, which will increase the hypoxia tolerance of endplate chondrocytes. Cell apoptosis is suppressed by the activation of HIF-1α in endplate chondrocytes under hypoxia condition.