CircN4BP2L2 promotes colorectal cancer growth and metastasis through regulation of the miR-340-5p/CXCR4 axis.

Colorectal cancer (CRC) is the third leading cause of cancer-related death worldwide. Dysregulation of circular RNAs (circRNAs) appears to be a critical factor in CRC progression. However, mechanistic studies delineating the role of circRNAs in CRC remain limited. In this study, qRT-PCR and western blot assays were used to measure the expression of genes and proteins. Migration, invasion, proliferation, and apoptosis were examined by wound-healing, transwell, CCK-8, colony formation, and flow cytometry assays, respectively. Molecular interactions were validated by a dual-luciferase report system. A xenograft animal model was established to examine in vivo tumor growth and lung metastasis. Our data indicated that circN4BP2L2 expression was increased in CRC tissues and cell lines. Notably, inhibition of circN4BP2L2 effectively inhibited proliferation, migration, and invasion of LoVo cells, and inhibited tumor growth and metastasis in vivo, whereas the forced expression of circN4BP2L2 facilitated the proliferation, migration, and invasion of HT-29 cells. Mechanistic studies revealed that circN4BP2L2 acted as a molecular sponge of miR-340-5p to competitively promote CXCR4 expression. Furthermore, inhibition of miR-340-5p reversed the anti-cancer effects of circN4BP2L2 or CXCR4 silencing. Our data indicated an oncogenic role of circN4BP2L2 in CRC via regulation of the miR-340-5p/CXCR4 axis, which may be a promising biomarker and target for CRC treatment.

CAF-derived midkine promotes EMT and cisplatin resistance by upregulating lncRNA ST7-AS1 in gastric cancer.

This study aimed to investigate the role of cancer-associated fibroblast (CAF)-derived midkine (MK) in cisplatin (DDP) resistance. The primary cultures of CAFs and non-cancer fibroblasts (NFs) were isolated and purified. The DDP-resistant gastric cancer (GC) cells were cultured with CAF-conditioned medium. QRT-PCR and Elisa assays were employed to determine MK expression. The expression of ST7-AS1 was measured by qRT-PCR. The impact of CAFs, MK, and ST7-AS1 silencing on DDP resistance was determined by MTT and Annexin V/PI staining assay. Expression of EMT markers and PI3K/AKT was determined by Western blot and qRT-PCR. The role of MK in DDP resistance was confirmed in a xenograft model. Incubation with CAF-conditioned medium increased the IC50 to DDP. Also, incubation with CAF-conditioned medium increased cell viability, reduced cell apoptosis, and promoted EMT in DDP-resistant GC cells, which were all blocked with MK neutralization antibody treatment. MK increased the DDP resistance and upregulated the expression of ST7-AS1 in DDP-resistant GC cells. Additionally, ST7-AS1 knockdown increased the sensitivity to DDP by inhibiting EMT. Moreover, ST7-AS1 knockdown significantly decreased the phosphorylation of PI3K and AKT, and suppressed EMT, which were restored by MK addition. Finally, MK promoted tumor growth and DDP resistance in a mice model bearing the SGC-7901/DDP xenografts. CAF-derived MK promotes EMT-mediated DDP resistance via upregulation of ST7-AS1 and activation of PI3K/AKT pathway.

HSP70 and mucin 5B: novel protein targets of N,N'-dinitrosopiperazine-induced nasopharyngeal tumorigenesis.

N,N'-Dinitrosopiperazine (DNP) induces nasopharyngeal carcinoma (NPC) and shows organ specificity to the nasopharyngeal epithelium. To investigate its mechanism, the rat NPC model was induced using DNP. Rat NPC and normal nasopharyngeal cells were obtained from the NPC model using laser capture. The total proteins from these cell samples were separated with two-dimension polyacrylamide gel electrophoresis techniques, and highly expressed proteins (> five-fold) were analyzed using matrix-assisted laser desorption/ionization time of flight and bioinformatics. The results showed that HSP70 and mucin 5B expression increased not only in rat NPC but also in atypical hyperplasia nasopharyngeal tissues, a precancer stage of NPC. High-expression of heat shock protein 70 (HSP70) and mucin 5B was further supported by western blot analysis. The immunofluorescence and western-blotting studies further showed that DNP induced the expression of HSP70 and mucin 5B in a dosage-dependent manner in normal nasopharyngeal epithelia cells. Our data indicate that DNP triggers over-expression of HSP70 and mucin 5B, and is involved in nasopharyngeal tumorigenesis. HSP70 and mucin 5B may be important targets in nasopharyngeal tumorigenesis induced by DNP.

[Cross-talk between ERK and NF-kappaB signal transduction pathways in the hepatocytes expressing hepatitis C virus nonstructural protein 3].

OBJECTIVE: To explore the cross-talk between extracellular signal-regulated kinase (ERK) and nuclear factor (NF-kappaB) signal transduction pathways in the hepatocytes expressing hepatitis C virus nonstructural protein 3 (HCV NS3). METHODS: A cell line QSG7701/NS3, which stably expressed HCV NS3 protein, was constructed by transfecting plasmid pcDNA3.1-NS3 into a human immortalized hepatocyte line QSG7701. Before and after QSG7701/NS3 cells were treated by MEK inhibitor PD98059, the phosphorylation level of ERK and the expression of cyclin D1 protein were detected by Western blot; the DNA binding activities of activator protein 1 (AP-1) and NF-kappaB were evaluated with electrophoretic mobility shift assay (EMSA). Cell cycles were measured by flow cytometry (FCM); the effects of PD98059 on the cell proliferation were determined by MTT assay. RESULTS: HCV NS3 protein could up-regulate the phosphorylation of ERK and the expression level of cyclin D1 in QSG7701 cells. PD98059 could inhibit the cell proliferation mediated by HCV NS3 protein, down-regulate the activities of AP-1 and NF-kappaB, and suppress the expression of cyclin D1. CONCLUSION: The inhibition of ERK can suppress the DNA binding activity of NF-kappaB and the cell proliferation mediated by HCV NS3 protein in a dose-dependent manner. There may be a cross-talk between ERK and NF-kappaB signal transduction pathways, which may exert synergistic action on the proliferation and malignant transformation of hepatocytes.

[AP-1 regulates TGF-beta1-induced secretion of Type I collagen in human lung fibroblasts].

OBJECTIVE: To investigate the role of AP-1 in the secretion of Type I collagen in TGF-beta1-stimulated human lung fibroblasts. METHODS: Human lung fibroblasts cell line (HLF-02) was cultured, and then stimulated with 10 microg/L TGF-beta1 at different time points. Curcumin was added into the culture medium to inhibit the AP-1 activity before incubating with TGF-beta1. AP-1 DNA binding activity was assayed by electrophoretic mobility shift assay (EMSA), and the expression of Type I collagen was detected by Western blot and RT-PCR. RESULTS: TGF-beta1 could induce the transcription and secretion of Type I collagen in HLF-02 cells(P<0.05). TGF-beta1 could upregulate the AP-1 DNA binding activity ( P<0.05). Curcumin ( 5, 10, 15, and 20 micromol/L) could inhibit the AP-1 DNA binding activity in TGF-beta1-stimulated cells (the inhibition ratio was 17.1%, 17.6%, 24.2%, and 31.3%; P<0.05). Curcumin (5, 10, 15, and 20 micromol/L) could also inhibit the secretion of Type I collagen significantly (the inhibition ratio was 62.1%, 58.8%, 62.1%, and 59.6%; P<0.05). CONCLUSION: AP-1 is responsible for the secretion of TGF-beta1-induced Type I collagen in human lung fibroblasts.

[Mechanism of hepatocyte transformation by HCV NS3 using two-dimensional electrophoresis and mass spectrometry].

OBJECTIVE: To investigate the proteome of hepatocyte transformation by hepatitis C virus (HCV) nonstructural protein 3 (NS3). METHODS: Human hepatocyte line QSG7701 stably expressing HCV NS3 C-terminal deleted protein was constructed, which was named pRcHCNS3/QSG. Two-dimensional electrophoresis (2-DE) was used to separate the total protein of pRcHCNS3/QSG and pRcCMV transfected cells (pRcCMV/QSG) respectively. Differentially expressed protein spots were identified by mass spectrometry. Western blot confirmed the differentially expressed proteins. RESULTS: 2-DE profiles with high resolution and reproducibility were obtained. The average spots of pRcHCNS3/QSG and pRcCMV/QSG were (1183+/-77) and (1095+/-82) respectively, and (920+/-60) spots were matched. Twenty-one differentially expressed protein spots were chosen randomly and 15 were identified by mass spectrometry. Some proteins such as Ras, P38 and HD53 which were involved in signal transduction were increased in pRcHCNS3/QSG cells. Western blot also showed strong expression of phosphorylated P44/42 and P38 in pRcHCNS3/QSG cells. Other differentially expressed proteins were related to cell cycle regulation, immunoreaction, tumor invasion and metastasis, and liver metabolizability. CONCLUSION: HCV NS3 might be involved in cell malignant transformation through affecting protein expression and signal transduction such as MAPK cascade. Further study on the signal transductions and their relationship would not only be helpful to explore the mechanism of HCV related HCC, but also provide a new idea for the molecular treatment of HCC.

Overexpression of ANLN contributed to poor prognosis of anthracycline-based chemotherapy in breast cancer patients.

PURPOSE: To investigate the associations of ANLN expression with prognosis of breast cancer and clinical outcome of anthracycline-based chemotherapy. METHODS: This study enrolled 308 breast cancer patients in which 264 of them received anthracycline-based chemotherapy. Immunohistochemistry was used to detect ANLN expression level of the patients. Clinical characteristics of the patients were collected, and associations of ANLN expression with prognosis were analyzed. RESULTS: Our results showed that ANLN expression was associated with survival of breast cancer patients, and it was also related to clinical outcome of patients received anthracycline-based chemotherapy. Breast cancer patients with high expression of ANLN would have poor prognosis and poor clinical outcome to anthracycline-based chemotherapy. CONCLUSION: ANLN could be an independent prognosis predictor for breast cancer, and its expression might be used to predict the anthracycline-based chemotherapy clinical outcome in breast cancer patients.

[Expression of Ang2 and Tie2 and their relation with the angiogenesis of hepatocellular carcinoma in rats].

OBJECTIVE: To investigate the relationship between the expression of Ang2, Tie2 and the angiogenesis of hepatocellular carcinoma in rats. METHODS: Thirty-eight healthy male rats were randomly divided into 3 groups: 5 rats in the control group; 25 rats in the experimental group were equally divided into 5-day, 10-day, 15-day, 20-day, and 25-day groups; the other 8 rats were used as the supplement of the experimental group. An allogenic transplanted rat model of CBRH-7919 hepatocellular carcinoma in situ was established by immunosuppression. The expressions of Ang2 and Tie2 were detected by immunohistochemical staining in cancerous tissues of different developmental stages and liver tissues of the control group. At the same time, microvessel density was determined by anti-CD31 immunohistochemical staining. RESULTS: CBRH-7919 hepatocellular carcinoma models were successfully set up in 24 rats. The expression level of Ang2 and Tie2 in cancerous tissues was much higher than that of liver tissues of the control group (P <0.05). The overexpression of Ang2 was pristine and continuous in different developmental stages. The expressions of Ang2 and Tie2 positively correlated with microvessal density in hepatocellular carcinoma (P<0.05). CONCLUSION: The up-regulation of Ang2 and Tie2 may play important roles in the angiogenesis of hepatocellular carcinoma. Ang2 may participate in the start of angiogenesis of hepatocellular carcinoma.

[Expression and role of nuclear transcription factor Sp1 in macrophages stimulated by silicon dioxide].

OBJECTIVE: To study the expression and localization of nuclear transcription factor Sp1 in macrophages after stimulated by silicon dioxide in vivo and in vitro. METHODS: Forty Sprague Dawley rats were randomly divided into the control group and the silica exposure group, 20 in each group. The rat silicosis models were established by direct tracheal instillation of silica into rat lung (0.2 g/kg) only once while the control group was instilled with equal amount of saline. Animals were killed at 1st, 7th, 14th, 21st and 28th day after instillation. Dynamic changes of Sp1 protein expression and its cellular localization were detected by immunohistochemistry in pulmonary macrophages. In vitro, Sp1 mRNA and protein expression and their dynamic changes were monitored by RT-PCR and western blotting after stimulated by silicon dioxide in cultured RAW264.7 macrophages respectively. Cellular localization of Sp1 protein was characterized by immunocytochemistry. RESULTS: Compared to the control group, the Sp1 protein expression was increased in pulmonary macrophages and reached the peak at the 14th day in the silica exposure group. In vitro, the Sp1 mRNA level began to rise at 30 minutes after the administration of silicon dioxide and reached the peak at 240 minutes and then decreased to the minimal level at 960 minutes. The Sp1 total protein and nuclear protein also exhibited the similar trend. The former reached the peak at 240 minutes and the latter at 480 minutes. The significant nuclear translocation of Sp1 protein was observed at 120 minutes after the administration of silicon dioxide and became most significant at 480 minutes. CONCLUSION: Silicon dioxide can activate nuclear transcription factor Sp1 in macrophages in vivo and in vitro. Sp1 might play an important pathogenic role in the development of silicosis.

[p38/ERK signal pathways regulating the expression of type I collagen and activity of MMP-2 in TGF-beta1-stimulated HLF-02 cells].

OBJECTIVE: To investigate the role of TGF-beta(1)/MAPK signaling pathways in the expression of type I collagen and activity of MMP-2, 9 in human lung fibroblasts. METHODS: Human lung fibroblasts cell line (HLF-02) was cultured and and then stimulated with 10 ng/ml TGF-beta(1) for different time; SB203580 or PD98059 was added into culture medium to block p38 or ERK kinase pathway before incubated with TGF-beta(1); the expression of type I collagen was detected by Western blotting and RT-PCR; zymogram analysis was used to analyze the activity of MMP-2 and MMP-9. RESULTS: (1) In the process of stimulation by TGF-beta(1), the type I collagen mRNA level of 24 h, 48 h and 72 h group was: 1.33 +/- 0.07, 2.46 +/- 0.09 and 2.39 +/- 0.08 respectively; and the type I collagen protein level of 24 h, 48 h and 72 h group was: 114.89 +/- 8.95, 208.16 +/- 6.75 and 211.46 +/- 8.05 respectively; and the activity of MMP-2 of 24 h, 48 h and 72 h group was: 190.33 +/- 5.86, 214.33 +/- 8.39 and 212.67 +/- 11.59 respectively. (2) SB203580 significantly inhibited the TGF-beta(1)-induced expression of type I collagen mRNA, protein and MMP-2 activity (inhibition ratio: 51%, 24% and 20%); (3) PD98059 also significantly attenuated the TGF-beta(1)-induced expression of type I collagen mRNA, protein and MMP-2 activity (inhibition ratio: 42%, 13% and 16%). CONCLUSION: TGF-beta(1) is capable of inducing the expression of type I collagen mRNA and protein and up-regulating MMP-2 activity in HLF-02 cells. p38 and ERK kinase signaling pathways play important role in regulation and control for this process.

Effect of hepatitis C virus nonstructural protein NS3 on proliferation and MAPK phosphorylation of normal hepatocyte line.

AIM: To study the effect of hepatitis C virus nonstructural region 3 (HCV NS3) protein on proliferation and transformation of normal human liver cell line. METHODS: QSG7701 cells were transfected with pRcHCNS3-5', pRcHCNS3-3' and pRcCMV using lipofectamine transfecting technique and selected with G418 method. Expression of HCV NS3 protein was determined by immunohistochemistry. Biologic characteristics of transfected cells were evaluated by population doubling time and soft agar assays. Activation of MAPK was analyzed using Western blot with phosphospecific monoclonal antibody against dually phosphorylated MAPK. RESULTS: QSG7701 cells transfected with pRcHCNS3-5' showed strong intracellular expression of HCVNS3 protein, and the positive signal was localized in cytoplasm. The expressing strength of HCVNS3 protein in pRcHCNS3-3'-transfected cells was weaker than that in pRcHCNS3-5'-transfected cells. The population doubling time in the transfected cells with pRcHCNS3-5' (12 h) was much shorter than those with pRcHCNS3-3', pRcCMV and normal cells (24, 26, 28 h, respectively) (P<0.01). The transfected cells with pRcHCNS3-5' showed much more anchorage independent colonies than that in those with pRcHCNS3-3' and pRcCMV (P<0.01). The cloning efficiencies of transfected cells with pRcHCNS3-5', pRcHCNS3-3', pRcCMV and controls were 33%, 1.33%, 1.46%, 1.11% respectively. The level of phosphorylated MAPK in the cells with pRcHCNS3-5' was much higher than that in those with pRcHCNS3-3'and pRcCMV and normal cells (P<0.01). CONCLUSION: The results suggest that (1) QSG7701 cells are a better human liver cell line for investigating the pathogenesis of HCV NS3 protein. (2) 5' region of the HCV genome segment encoding HCV NS3 is involved in cell growth and cell phenotype. (3) HCV NS3 N-terminal peptide may up-regulate the activation of MAPK, but not affect the expression of MAPK.

Significance and relationship between infiltrating inflammatory cell and tumor angiogenesis in hepatocellular carcinoma tissues.

AIM: To investigate the relationship between infiltrating inflammatory cell and tumor angiogenesis in hepatocellular carcinoma (HCC) tissues and their clinicopathological features. METHODS: The paraffin-embedded specimens from 70 cases with HCC were stained using EliVision immunohistochemistry with mAbs against CD68, tryptase, and CD34. The counts of tumor-associated macrophage (TAM), mast cell (MC) and tumor microvessel (MV) were performed in the tissue sections. RESULTS: The mean counts of TAM, MC, and MV in HCC tissues were significantly higher than those in pericarcinomatous liver tissues (TAM: 69.31+/-11.58 vs 40.23+/-10.36; MC:16.74+/-5.67 vs 7.59+/-4.18; MV: 70.11+/-12.45 vs 38.52+/-11.16, P<0.01). The MV count in the patients with metastasis was markedly higher than that with non-metastasis (P<0.01). In addition, the MC count in the patients with poorly differentiated HCC was obviously higher than that with well differentiated HCC (P<0.01). The correlation analysis showed that the TAM count was significantly correlated with the count of MV (r=0.712, P<0.01), and the MC count was obviously correlated with the MV count (r=0.336, P<0.05). CONCLUSION: TAM and MC might be closely related to the enhancement of tumor angiogenesis. The MV count might be associated with tumor invasion and metastasis. Moreover, the MC count might be associated with tumor differentiation and prognosis of HCC.

[The effects of hepatitis C virus core protein on biological behaviors of human hepatocytes].

OBJECTIVE: To investigate the effects of hepatitis C virus (HCV) core protein on the biological behaviors of human hepatocytes and their underlying mechanism. METHODS: A cell line expressing stably HCV core protein-QSG7701/core was constructed by transfecting the plasmid pcDNA3.1-core (expressing HCV core protein) into the human immortalized hepatocytes of the line QSG7701. The biological behaviors of these transfected cells were observed through plating-efficiency test, growth curve and flow cytometry (FCM). The association between HCV core protein and the expression of activated caspase-3 protein was evaluated by immunocytochemistry. The phosphorylation of mitogen-activate protein kinases (MAPKs) was detected with Western blotting. The activation of nuclear transcriptors AP-1, important effector molecule of MAPKs, and nuclear factor-kappa binding (NF-kappaB) were evaluated with luciferase assays and electrophoretic mobility shift assay (EMSA). RESULTS: HCV core protein was expressed in the QSG7701/core cells and not in the QSG7701/pcDNA3.1 cells and untransfected QSG7701 cells. There were no significant differences in the expression levels of total P44/42(MAPK), p38(MAPK) and JNK among the QSG7701/core cells, QSG7701/pcDNA3.1 cells and untransfected QSG7701 cells. The expression levels of phophorylated P44/42(MAPK), p38(MAPK) and JNK in the QSG7701/core cells were significantly weaker than those in the QSG7701/pcDNA3.1 cells and untransfected QSG7701 cells. Plating efficiency test showed that the clone formation rate of the QSG7701/core cells was 32.25%, significantly lower than those of QSG7701/pcDNA3.1 and untransfected QSG7701 cells (47.5% and 42.5% respectively, both P < 0.01). The growth curve showed that the multiplication time of the QSG7701/core cells was 36 hours, significantly longer than those of the QSG7701/pcDNA3.1 and untransfected QSG7701 cells (27 and 28 hours respectively). FCM showed that the apoptotic rate of the QSG770/1core was 1.04%, lower than those of the QSG7701/pcDNA3.1 and untransfected QSG7701 cells (1.68% and 3.7% respectively), and that the percentage of theQSG770/1core cells at the G(0)/G(1) stage increased and those in the S stage decreased. Immunocytochemistry showed that the expression intensity of caspase-3 in the QSG7701/core cells was significantly weaker than those of the QSG7701/pcDNA3.1 cells and untransfected QSG7701 cells. CONCLUSION: HCV core protein suppresses cell proliferation and apoptosis by downregmicrolating the phosphorylation of MAPKs and activating the transcriptors AP-1 and NF-kappaB, thus promoting the persistency of HCV infection which leads to chronic hepatitis C and hepatocellular cancer.

[Apoptosis and caspase-3 in the model of rat silicosis].

OBJECTIVE: To explore the changes of apoptosis of cells in the lung tissue of rats with silica instillation and to its significance in silicosis, and to clarify the role of caspase-3 in the apoptosis progress. METHODS: Forty-eight rats were randomly divided into saline control groups and silica instillation groups, and the silicosis model was established in rats. Flow cytometry was used for detecting the rate of apoptosis at various stages. Immunohistochemistry for the expression of cleaved caspase-3. RESULTS: The model of rat silicosis was established successfully. The apoptosis rate in the experimental group was significantly higher than that in the control group, and was increased with time. Caspase-3 was mainly expressed in alveolar epithelium cells, pulmonary macrophages and infiltrated inflammation cells. The expression of caspase-3 in the experimental group was stronger than that in the control group, but its expression intensity was not related to the cell apoptosis (r = 0.215, P > 0.05). CONCLUSION: The apoptosis of the lung cells plays an important role during rat silicosis genesis. Caspase-3 plays an important role in regulating cell apoptosis during rat silicosis genesis.

[Regulation of hepatitis C virus core protein on the activity of signal transducers and activators of transcription 3].

OBJECTIVE: To investigate the regulation of hepatitis C virus (HCV) core protein on the activity of signal transducers and activators of transcription 3 (stat3). METHODS: A cell line expressing stable HCV core protein-QSG7701-core was constructed by transfecting the pcDNA3. 1-core (expressing HCV core protein) into the human immortalized hepatocyte line QSG7701. The phosphorylation and DNA binding activity of stat3 were detected by immunocytochemistry, Western blot, and electrophoretic mobility shift assay (EMSA). RESULTS: The expression level of phosphorylated stat3 in QSG7701-core cells was significantly lower than that in QSG7701-pcDNA3. 1 cells and untransfected QSG7701 cells, but there were no significant differences in the expression levels of total stat3 among the 3 groups. The positive signal of phosphorylated stat3 in nucleus of QSG7701-core cells was obviously weaker than that in QSG7701-pcDNA3. 1 cells and untransfected QSG7701 cells. EMSA showed that DNA binding activity of stat3 in QSG7701-core cells significantly decreased. CONCLUSION: The expressionof HCV core protein in human hepatocyte line may suppress the phosphorylation and DNA binding activity of stat3, which may be one of the causes for resistance against interferon.

[Effects of silica on the expression of plasminogen activator inhibitor-1 and activator protein-1 in human alveolar epithelial cells type II].

OBJECTIVE: To investigate the mechanism of silicosis by observing the effects of silica on the expression of plasminogen activator inhibitor-1 (PAI-1) and activator protein-1 (AP-1) in human alveolar epithelial cells type II (A549). METHODS: A549 cell and SiO(2) (200 microg /ml) were co-cultured for 0, 4, 8, 16 and 24 h respectively. The reverse transcriptase polymerase chain reaction (RT-PCR), Western blotting and SP immunocytochemistry were used for detections of the PAI-1 mRNA and protein expression. The nucleoprotein and total protein expression of AP-1 were investigated by Western blotting. RESULTS: The expression levels of PAI-1 mRNA and protein were increased in a time-dependent manner(r(mRNA) = 0.911, r(protein) = 0.902, P < 0.05). The expressions of PAI-1 mRNA and protein in experimental groups were higher than that in control group (P < 0.05) and was the highest in 24 h group [(0.73 +/- 0.01) vs (0.36 +/- .03)]. The nucleoprotein expressions of c-jun/c-fos in experimental groups were also higher than in control group (P < 0.05), and the nucleoprotein expression level of c-jun was the highest in 4 h group [(1.54 +/- 0.02) vs (0.56 +/- 0.03)]; the nucleoprotein expression level of c-fos was the highest in 8 h group [(0.36 +/- 0.01) vs (0.15 +/- 0.01)]. Both c-jun and c-fos expression were decreased after 16 h, but the total protein expression of c-jun/c-fos had no difference in all experimental groups. The positive signal of PAI-1 was located in cytoplasm and nucleus. CONCLUSION: SiO(2) could induce PAI-1 expression of A549 in a time-dependent manner, and AP-1 activation can be observed in early time.

[Transforming growth factor-beta1 induced phenotypic differentiation of human lung fibroblasts through mitogen activated protein kinase-dependent pathway].

OBJECTIVE: To investigate the role of MAPK signal transduction in TGF-beta1 induced phenotypic differentiation of human lung fibroblasts. METHOD: Human lung fibroblasts cell line (HLF-02) were cultured and then stimulated with 10 ng/ml TGF-beta1 for different time; SB203580 or PD98059 was added into culture medium to prevent p38 or Erk kinase pathway before incubating with TGF-beta1; the expression of alpha-smooth muscle actin (alpha-SMA) was detected by Western blotting and RT-PCR; Western blotting was used to assay phosphorylation of p38, Erk, and JNK kinase. RESULTS: (1) In the process of stimulation by TGF-beta1, the alpha-SMA mRNA expression levels of 24, 48 and 72 h groups were 1.87 +/- 0.11, 2.49 +/- 0.10, 3.02 +/- 0.15 respectively; and the alpha-SMA protein expression levels of 24, 48 and 72 h groups were 3.20 +/- 0.14, 3.96 +/- 0.21, 4.57 +/- 0.13 respectively. (2) TGF-beta1 induced p38, Erk kinase phosphorylation but not JNK kinase. (3) The inhibitors SB203580 and PD98059 suppressed TGF-beta1-induced p38 kinase and Erk phosphorylation respectively. (4) SB203580 significantly attenuated TGF-beta1-induced alpha-SMA mRNA and protein expression (inhibition rate: 30% and 40%); PD98059 also significantly inhibited TGF-beta1-induced alpha-SMA mRNA and protein expression (inhibition rate: 10% and 20%). CONCLUSION: TGF-beta1 is capable of inducing the phenotypic differentiation of HLF-02, which is regulated by p38 and Erk kinase signal pathway.

Expression of immunoglobulin kappa light chain constant region in abnormal human cervical epithelial cells.

Although it is generally believed that, under normal conditions, the only source of immunoglobulin is mature B lymphocytes, we recently found several epithelium-derived carcinoma cell lines also express immunolglobulin-like protein. We extended our study to biopsy samples of human cervical tissues with various epithelial lesions. By in situ hybridization, we only detected a low level of mRNA for the immunoglobulin kappa light chain constant region in epithelia with cervicitis. However, in epithelia with dysplasia and carcinoma, the expression of mRNA for the kappa constant region was markedly increased. There was no significant difference in the level of mRNA for the kappa constant region between epithelial dysplasia and carcinoma. The aberrant expression of immunoglobulin kappa light chain constant region in dysplastic and cancerous cervical epithelial cells may serve as a marker for malignant cell transformation.

Hepatocyte transformation and tumor development induced by hepatitis C virus NS3 c-terminal deleted protein.

AIM: To study the effect of hepatitis C virus nonstructural protein 3 c-terminal deleted protein (HCV NS3-5') on hepatocyte transformation and tumor development. METHODS: QSG7701 cells were transfected with plasmid pRcHCNS3-5' (expressing HCV NS3 c-terminal deleted protein) by lipofectamine and selected in G418. The expression of HCV NS3 gene and protein was determined by PCR and immunohistochemistry respectively. Biological behavior of transfected cells was observed through cell proliferation assay, anchorage-independent growth and tumor development in nude mice. The expression of HCV NS3 and c-myc proteins in the induced tumor was evaluated by immunohistochemistry. RESULTS: HCV NS3 was strongly expressed in QSG7701 cells transfected with plasmid pRcHCNS3-5' and the positive signal was located in cytoplasm. Cell proliferation assay showed that the population doubling time in pRcHCNS3-5' transfected cells was much shorter than that in pRcCMV and non-transfected cells (24 h, 26 h, 28 h respectively). The cloning ratio of cells transfected with pRcHCNS3-5', pRcCMV and non-transfected cells was 33 %, 1.46 %, 1.11 %, respectively, the former one was higher than that in the rest two groups (P<0.01). Tumor development was seen in nude mice inoculated with pRcHCNS3-5' transfected cells after 15 days. HE staining showed its feature of hepatocarcinoma, and immunohistochemistry confirmed the expressions of HCV NS3 and c-myc proteins in tumor tissue. The positive control group inoculated with HepG2 also showed tumor development, while no tumor developed in the nude mice injected with pRcCMV and non-transfected cells after 40 days. CONCLUSION: 1.HCV NS3 c-terminal deleted protein has transforming and oncogenic potential. 2. Human liver cell line QSG7701 may be used as a good model to study HCV NS3 pathogenesis.

[Hepatocyte transformation and tumor development induced by hepatitis C virus NS3 N-terminal protein].

OBJECTIVE: To study the effect of hepatitis C virus nonstructural protein 3 N-terminal protein (HCV NS3-5') on hepatocyte transformation and tumor development. METHODS: QSG7701 cells were transfected with plasmid pRcHCNS3-5' (expressing HCV NS3 N-terminal protein) by lipofectamine and selected in G418. The expression of HCV NS3 gene and protein was determined by PCR and immunohistochemistry respectively. Biological effect of transfected cells was observed through cell proliferation assay, anchor independent growth, and tumor development in nude mice. The expression of HCV NS3 and c-myc protein in the induced tumor was evaluated by immunohistochemistry. RESULTS: HCV NS3 was strongly expressed in QSG7701 cells transfected with plasmid pRcHCNS3-5' and the positive signal was located in cytoplasm. The HCV NS3 expression and c-myc protein in the induced cytoplasm. Cell proliferation assay showed that the population doubling time in the pRcHCNS3-5' transfected cells was much shorter than that in the pRcCMV and non-transfected cells (24 h, 26 h, 28 h respectively). The cloning efficiencies of transfected cells with pRcHCNS3-5', pRcCMV and non-transfected cells were 33.0%, 1.5%, 1.1% respectively (P < 0.01). Tumor developed in nude mice inoculated with pRcHCNS3-5'transfected cells 15 days after the inoculation. HE staining showed hepatocarcinoma character and immunohistochemistry confirmed HCV NS3 and c-myc expression in the tumor tissue. The positive control group also showed tumor development, while no tumor mass obtained in the nude mice inoculated with pRcCMV and non-transfected cells even 40 days after the injection. CONCLUSION: HCV NS3 N-terminal protein showed cell transformation and tumorigenic features.