Role of epithelial-to-mesenchymal transition in the pulmonary fibrosis induced by paraquat in rats.

BACKGROUND: This study aims to explore the characteristics of the epithelial-to-mesenchymal transition (EMT) process and its underlying molecular mechanisms in the period of paraquat (PQ)-induced pulmonary fibrosis (PF). METHODS: Picrosirius red staining and collagen volume fraction were utilized to evaluate the pathological changes of PQ-induced PF in rats. Immunohistochemistry, Western blot, and real-time reverse transcriptase-polymerase chain reaction (RT-PCR) were used to measure the protein and gene expression of EMT markers, EMT-associated transcription factors, and regulators of EMT-related pathways, respectively. RESULTS: The collagen deposition in the alveolar septum and increased PF markers were characteristics of pathological changes in PQ-induced PF, reached a peak on day 14 after PQ poisoning, and then decreased on day 21. The protein and gene expression of the fibrosis marker, EMT markers, transcription factors, and regulators of EMT-related signaling pathways significantly increased at different time points after PQ poisoning compared with corresponding controls (P<0.05), and most of them reached a peak on day 14, followed by a decrease on day 21. The gene expression of EMT markers was significantly correlated with PF markers, transcription factors, and regulators of EMT-related signaling pathways (P<0.05). The mRNA expression of transcription factors was significantly correlated with that of TGF-ß1 and Smad2 (P<0.05 or P<0.01), instead of Wnt2 and ß-catenin (P>0.05). CONCLUSIONS: EMT process plays a role in the PQ-induced PF, in which most PF and EMT markers have a peak phenomenon, and its underlying molecular mechanisms might be determined by further studies.

MYC-regulated lncRNA NEAT1 promotes B cell proliferation and lymphomagenesis via the miR-34b-5p-GLI1 pathway in diffuse large B-cell lymphoma.

BACKGROUND: LncRNA NEAT1 has been identified as a tumour driver in many human cancers. However, the underlying mechanism of lncRNA NEAT1 in diffuse large B-cell lymphoma (DLBCL) progression is unclear. METHODS: The expression levels of NEAT1, GLI1 and miR-34b-5p were detected by RT-qPCR and Western blotting in DLBCL tissues and cell lines. MTT and colony formation assays were performed to examine cell proliferation, while annexin-V staining and TUNEL assays were performed to measure cell apoptosis. The effect of NEAT1, GLI1 and miR-34b-5p on cell cycle-associated proteins was evaluated by Western blotting. Dual-luciferase reporter and RNA immunoprecipitation (RIP) assays were employed to investigate the interaction between NEAT1 and miR-34b-5p or GLI1 and miR-34b-5p. Moreover, chromatin immunoprecipitation (ChIP) was performed to demonstrate the interaction between MYC and NEAT1. RESULTS: NEAT1 and GLI1 were upregulated while miR-34b-5p was downregulated in DLBCL tissues and cell lines compared to normal controls. Knockdown of NEAT1 or overexpression of miR-34b-5p inhibited cell proliferation but promoted cell apoptosis. Overexpression of NEAT1 reversed GLI1-knockdown induced attenuation of cell proliferation. In other words, NEAT1 acted as a competing endogenous RNA (ceRNA), regulating the miR-34b-5p-GLI1 axis, further affecting the proliferation of DLBCL. Moreover, MYC modulated NEAT1 transcription by directly binding to the NEAT1 promoter. CONCLUSION: We revealed that MYC-regulated NEAT1 promoted DLBCL proliferation via the miR-34b-5p-GLI1 pathway, which could provide a novel therapeutic target for DLBCL.

Cripto-1 expression in patients with clear cell renal cell carcinoma is associated with poor disease outcome.

BACKGROUND: Cripto-1 (CR-1) has been reported to be involved in the development of several human cancers. The potential role of CR-1 in clear cell renal cell carcinoma (ccRCC) is still not clear. METHODS: CR-1 expression was evaluated in ccRCC tissues by Real-time quantitative PCR, Western blot and immunohistochemistry. Serum levels of CR-1 were tested by enzyme-linked immunosorbent assay (ELISA). The clinical significance of CR-1 was analyzed. The effects of CR-1 on cell proliferation, migration, invasion and angiogenesis were investigated in ccRCC cell lines in vitro and in vivo, and markers of the epithelial -mesenchymal transition (EMT) were analyzed. The impact of CR-1 on Wnt/ß-catenin signaling pathway was also evaluated in vitro and in vivo. RESULTS: CR-1 expression was elevated in ccRCC tumor tissues and serum samples. CR-1 expression was correlated with aggressive tumor phenotype and poor survival. Ectopic expression of CR-1 significantly promoted cell proliferation, migration, invasion and angiogenesis whereas knockdown of CR-1 inhibited these activities both in vitro and in vivo. Moreover, we found that CR-1 induced EMT and activated Wnt/ß-catenin signaling pathway both in vitro and in vivo. CONCLUSIONS: These results suggest that CR-1 is likely to play important roles in ccRCC development and progression, and that CR-1 is a prognostic biomarker and a promising therapeutic target for ccRCC.

[Influence of rosiglitazone and all-trans-retinoic acid on angiogenesis and growth of myeloma xenograft in nude mice].

OBJECTIVE: To observe the effect of rosiglitazone (RGZ) and all-trans-retinoic acid (ATRA) on the growth of myeloma xenograft in nude mice and to explore the influence of RGZ and ATRA on VEGF expression and angiogenesis in the tumor. METHODS: VEGF gene expression in myeloma cell line U266 cells was analyzed by semi-quantitative RT-PCR after incubation with RGZ, ATRA, or RGZ + ATRA for 24 h. Myeloma xenograft was established by subcutaneous injection of 10(7) U266 cells in the scapula area of 4-week old nude mice. 7 days later, the nude mice were administered with RGZ, ATRA or RGZ + ATRA, respectively, by intraperitoneal injection once every day for 21 days. The control mice were given equal volume of normal saline instead of the drug. On the 21(st) day of treatment, the mice were sacrificed and the tumors were taken off, and the tumor volume and weight were measured. The tumors were examined by histopathology with HE staining, and microvessel density (MVD), CD34 and VEGF expression in the tumors were analyzed by immunohistochemical staining. RESULTS: VEGF mRNA was highly expressed in U266 cells and was decreased in a dose-dependent manner after incubation with RGZ. The VEGF mRNA level was further more decreased after RGZ + ATRA treatment. Xenografts of U266 cells were developed in all nude mice. The volume and weight of xenografts in the RGZ group were (785 ± 262) mm(3) and (1748 ± 365) mg, respectively, significantly lower than those of the control group (both P < 0.01). More significant inhibition was in the RGZ + ATRA group, (154 ± 89) mm(3) and (626 ± 102) mg, respectively, both were P < 0.05 vs. the RGZ group. RGZ inhibited the angiogenesis in U266 xenografts and immunohistochemical staining showed that the tumor MVD and VEGF expression were significantly decreased by RGZ treatment, and further more inhibited in the RGZ + ATRA group. VEGF protein was expressed in all xenografts in the nude mice. Its immunohistochemical staining intensity was 2.20 ± 0.40 in the control group, significantly higher than that of 1.48 ± 0.37 in the RGZ group (P < 0.01), and that of RGZ + ATRA group was 0.58 ± 0.26, further significantly lower than that of the RGZ group (P < 0.01). CD34 was expressed in all xenografts, most highly in the control group and lowest in the RGZ + ATRA group. The microvessel density (MVD) was highest in the control group (56.4 ± 15.2), significantly lower in the RGZ group (44.6 ± 11.2) (P < 0.05), and lowest in the RGZ + ATRA group (21.5 ± 8.6, P < 0.01). CONCLUSIONS: The growth of myeloma cells can also be inhibited by RGZ and ATRA in nude mice in vivo. In addition to differentiation and apoptosis induction, RGZ can inhibit the formation of myeloma xenograft probably also through the downregulation of VEGF expression and subsequent angiogenesis.

[Establishment of murine allogeneic umbilical cord blood cell transplantation model and study on the mechanism of keratinocyte growth factor enhancing immune reconstitution after transplantation.].

OBJECTIVE: To explore the impact and mechanism of keratinocyte growth factor (KGF) on immune reconstitution post murine allogeneic umbilical cord blood transplantation (UCBT). METHODS: Perpheral blood (PB) from 19.5-day embryos post-conception (E 19.5 d) mice was used as umbilical cord blood (UCB) graft. Thirty-two BALB/c mice were randomly assigned to 4 groups with 8 mice each in the first cohort UCBT. Mice were infused with PBS (control group) or 1 x 10(6) (group 1A), 2 x 10(6) (group 1B), 3 x 10(6) UCB mononuclear cells (MNCs) (group 1C), respectively. Twenty-four BALB/c mice were randomly assigned to 3 groups with 8 mice each in the second cohort UCBT. Mice were injected with 1 x 10(6) (group 2A), 2 x 10(6) (group 1B) or 3 x 10(6) (UCB) MNCs (group 2C). All mice received platelet transfusion on +8d. Sixteen BALB/c mice were randomly assigned to 2 groups with 8 mice each in the third cohort UCBT. Mice were injected s.c. with KGF (group 3) or PBS (control group) before TBI. All mice were injected with 2 x 10(6) UCB MNCs and were supported with platelet transfusion on +8 d. The survival time, splenic lymphoid cell subsets, sjTREC assay were observed after UCBT. RESULTS: The 100-day survival of mice were 2, 3 and 3 in group 1A, 1B, 1C and 7, 8, 8 in group 2A, 2B, 2C, respectively. The splenic T, NKT, NK and B cell counts on +35 d were (9.57 +/- 0.74) x 10(6), (0.64 +/- 0.06) x 10(6), (1.43 +/- 0.10) x 10(6) and (19.13 +/- 1.50) x 10(6) in control group, respectively; while were (13.47 +/- 0.74) x 10(6), (0.89 +/- 0.03) x 10(6), (1.79 +/- 0.04) x 10(6) and (20.50 +/- 0.91) x 10(6) in group 3, respectively, being significantly higher than in control group. The sjTREC level was 182.2 +/- 10.7copies per 10(5) cells in control group; while was 224.2 +/- 9.6 copied per 10(5) cells in group 3, being significantly higher than in control group (P = 0.019). CONCLUSIONS: Peripheral blood from E19.5d is rich in hematopoietic stem cells. A murine allogeneic UCBT model with platelet support on +8 d is established. KGF treatment can enhance thymic output and improve T cell immune reconstitution after UCBT.

[Advances of study on PPARgamma/PPARgamma ligand in hematologic malignancies].

Recently, along with the thorough investigation on the gene and molecular biology of peroxisome proliferators activated receptorgamma (PPARgamma), the therapeutic effects of PPARgamma ligand and its potential mechanism were gradually recognized. PPARgamma will probably become a new target of oncotherapy and is now extensively followed by researchers. This review focuses the advances of study on PPARgamma distribution in tissue, its function, its ligand in relationship with hematologic malignancies including acute myeloid leukemia, acute lymphocytic leukemia, chronic myeloid leukemia, lymphoma, multiple myeloma and so on.

[5-azacytidine treatment induces tumor suppressor gene XAF1 expression and inhibits proliferation in myeloma cells].

OBJECTIVE: To investigate the effect of 5-azacytidine on XAF1 expression in myeloma cell lines RPMI8226 and XG-7 and the in vitro anti-myeloma activity of 5-azacytidine. METHODS: XAF1 mRNA and protein expression was detected by semi-quantitative reverse transcriptase PCR and Western blot, respectively. Methylation specific PCR (MSP) was used to detect methylation status of XAF1 promoter CpG islands. RPMI8226 and XG-7 cells were treated with 0-5 micromol/L of 5-azacytidine and Cell Counting Kit-8 colorimetric assay was used to evaluate the growth inhibitory effect. Cell apoptosis was determined with Annexin V-PE/7-AAD staining by flow cytometry. RESULTS: Untreated RPMI8226 cells expressed XAF1 mRNA isoforms 1 and 2, and untreated XG-7 cells had no XAF1 expression. Hypermethylation of XAF1 promoter CpG islands was detected in both the cell lines. After treated with 2.5 micromol/L 5-azacytidine for 72 h, both the cell lines expressed full-length XAF1 transcript and protein. 5-azacytidine treatment led to XAF1 promoter CpG islands hypomethylation and showed anti-myeloma activity in a time- and concentration-dependent manner with IC50 of 2.4 micromol/L and 2.6 micromol/L at 48 h for RPMI8226 and XG-7 cell lines, respectively. CONCLUSIONS: Lack of XAF1 expression and abnormal expression of XAF1 in myeloma cell lines are associated with XAF1 gene promoter CpG islands hypermethylation. 5-azacytidine treatment can induce XAF1 mRNA and protein expression and exerts anti-myeloma activity via apoptosis at clinically achievable concentrations.

[Rosiglitazone and all-trans retinoic acid inhibit human myeloma cell proliferation via apoptosis signaling pathway modulation].

OBJECTIVE: To investigate the effects of artificial ligand of peroxisome proliferators activated receptors (PPARs), rosiglitazone (RGZ) and all trans-retinoic acid (ATRA) on human myeloma cell line growth in vitro and in vivo. METHODS: U266 and RPMI 8226 cells were treated with different concentration of RGZ in the presence or absence of ATRA and the results were studied by 3H-TdR thymidine incorporation (for cells proliferation), Annexin V-PI staining and caspase-3 activity assay (for cells apoptosis), RT-PCR (for FLIP, XIAP and survivin mRNA expression), and tumor formation test in BALB/c nude mice. RESULTS: Exposure to RGZ induced proliferation inhibition in a dose-dependent manner in both U266 (r = 0.991, P < 0.01) and RPMI 8226 cells (r = 0.961, P < 0.01). A combination of RGZ with ATRA could enhance the inhibition effect (P < 0.001 in U266, P < 0.01 in RPMI8226). 10 micromol/L of RGZ induced apoptosis of (9.8 +/- 1.7)% in U266 cells and (10.7 +/- 3.3)% in RPMI8226 cells, in a time and dose dependent manner and combined with ATRA intensified the apoptosis induction effects (P < 0.01 in both cell lines). The FLIP, XIAP and survivin mRNAs were expressed in both cell lines and their levels decreased significantly after cultured with RGZ. The addition of RGZ + ATRA in the culture further decreased the levels. Caspase-3 activity increased substantially with the increase of RGZ concentration and the addition of RGZ + ATRA in the culture medium showed similar synergism effect on caspase-3 activation (P < 0.01). The xenograft of U266 cells in BALB/c nude mice were inhibited by RGZ and so did more by the combination of RGZ and ATRA (P < 0.01). CONCLUSION: The down-regulation of FLIP, XIAP and Survivin induced by RGZ can activate caspase-3, whereby induced apoptosis and proliferation inhibition in myeloma cells. ATRA can enhance these effects of RGZ.

Preliminary study on 5-azacytidine anti-myeloma activity in vitro.

This study was aimed to investigate the effect of 5-azacytidine (5-AZA) on XAF1 expression in myeloma cells and efficacy of 5-AZA treatment for myeloma in vitro. XAF1 expression was analyzed by semi-quantitative PCR. Methylation-specific PCR (MSP) was used to detect the methylation status of XAF1 promoter CpG islands. RPMI 8226 and XG-7 cells were treated with 0-5 micromol/L of 5-AZA. Expression of XAF1 mRNA variants was confirmed by gel electrophoresis. The results indicated that the untreated RPMI 8226 cell expressed XAF1 mRNA transcript 1 and transcript 2, untreated XG-7 cells did not express XAF1 mRNA. Hypermethylation of XAF1 promoter CpG islands could be detected in both cell lines. Both cell lines expressed full-length XAF1 transcript after being treated with 2.5 micromol/L of 5-AZA for 72 hours. 5-AZA treatment led XAF1 promoter CpG island to hypomethylation in both cell lines. 5-AZA exerted anti-myeloma activity in a time- and concentration-dependent manner. The IC(50) value of XG-7 cells treated with 5-AZA for 48 hours was 2.6 micromol/L. 1.0, 2.0, 2.5 and 5.0 micromol/L of 5-AZA treatment for 48 hours induced (34.3 +/- 8.0)%, (54.8 +/- 3.1)%, (64.1 +/- 3.4)%, (81.0 +/- 4.1)% apoptosis in XG-7 cell line respectively. The combination of 1.0 - 4.0 micromol/L of 5-AZA with 1.0 - 4.0 micromol/L of arsenic trioxide (ATO) exhibited synergistic toxicity in myeloma cells with all CI values less than 1.0. It is concluded that lack of XAF1 expression and abnormal expression of XAF1 in myeloma cell lines are associated with the hypermethylation of XAF1 gene promoter CpG island. 5-AZA treatment can induce the expression of XAF1 mRNA and protein in myeloma. 5-AZA exerts anti-myeloma activity via apoptosis at clinically achievable concentrations. The findings suggested that 5-AZA and ATO may be an effective combination in the therapy of patients with multiple myeloma.

[Differentiating effect of PPARgamma ligand rosiglitazone and all trans-retinoic acid on myeloma cells and its possible mechanism].

OBJECTIVE: To investigate the effects of PPARgamma ligand (rosiglitazone, RGZ) as well as combined with all trans-retinoic acid (ATRA) on human myeloma cells and try to explore the possible mechanism. METHODS: Human myeloma cell lines U266 and RPMI-8226 cells were treated with RGZ in the presence or absence of ATRA. Cell proliferation was evaluated by [(3)H] thymidine incorporation, cell cycle distribution and CD49e expression were analyzed by flow cytometry, morphology changes were evaluated by Wright-Giemsa staining, and p27(Kip1) and p21(Waf1) expression was detected by Western blotting. RESULTS: The exposure to RGZ induced proliferation inhibition in both cell lines in a dose-dependent manner. After cultured with 5 micromol/L RGZ, the proportion of U266 and RPMI-8226 cells in phase G(0)/G(1) was (45.2 +/- 6.7)% and (40.3 +/- 7.3)%, respectively (P < 0.05). The proportion of the cells in phase G(2)/M and S was (52.2 +/- 7.4)% and (57.4 +/- 9.5)%, respectively (P < 0.05). These changes were more evident when the RGZ concentration was increased to 10 micromol/L. A combination of RGZ with ATRA enhanced the growth inhibition and cell cycle arrest effects of RGZ. The RGZ-treated myeloma cells displayed morphological characteristics of cell differentiation, and more evident signs of differentiation were observed when RGZ was combined with ATRA. These changes were confirmed by the detection of CD49e expression. The expression of p27(Kip1) and p21(Waf1) in myeloma cells was up-regulated by RGZ and this change was more apparent when RGZ was used in combination with ATRA. CONCLUSION: RGZ can induce cell cycle arrest and cell differentiation in myeloma cells which maybe caused by up-regulation of p27(Kip1) and p21(Waf1) expression. ATRA can enhance these effects of RGZ on multiple myeloma cells and combined use of these two drugs may show a synergistic effect on myeloma cells.