Expression of CSN Complex in ATRA-induced APL Cell Differentiation and Its Clinical Significance / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To investigate the expression of CSN complex (COP9 signal some subunits) in the patients with acute promyelocytic leukemia (APL) and its significance in the ATRA-induced APL differentiation.</p><p><b>METHODS</b>Using the NB4 cells as a model, morphologic observation and myeloid differentiation marker CD11b detection were used to monitor ATRA-induced APL differentiation, the expression of CSN complex in cell differentiation was detected by Western blot and reverse transcription real time fluorescent quantitative PCR (RT-qPCR) method. RT-qPCR was also used to detect the relative expression level of COP9 signalosome subunits in the APL patients and remission after treatment.</p><p><b>RESULTS</b>ATRA could obviously enhance CD11b expression; the cell morphology showed obvious differentiation characteristics. During the differentiation, the expression of COP9 signalosome subunits was down-regulated by ATRA. Meanwhile, the CSN expression level in newly diagnosed APL patients was much higher than that in controls (non-leukemia) (P < 0.05). The level of CSN expression was obviously down-regulated when APL patients achieved complete remission.</p><p><b>CONCLUSION</b>The high CSN expression level in APL patients can be down-regulated by ATRA. CSN complex may have a significant effect on the pathogenesis and therapy of APL.</p>

Uchl1 and its associated proteins were involved in spermatocyte apoptosis in mouse experimental cryptorchidism / 生理学报

Uchl1 was found to be involved in spermatocyte apoptosis. The aim of the present study was to test whether Uchl1 and its associated proteins Jab1 and p27(kip1) were involved in spermatogenic damages in response to heat-stress in cryptorchidism. Hematoxylin and eosin (HE) staining and DNA end labeling (TUNEL) were used to observe morphological and apoptotic characteristics of spermatogenic cells; Immunohistochemical analysis was used to detect changes of Uchl1 and its associated proteins Jab1 and p27(kip1) in response to heat-stress from cryptorchidism leading to spermatocyte losses; And protein affinity analysis (pull-down) and immunofluorescence co-localization were used to verify the relevance among the three proteins in spermatocytes. The results showed that, Jab1 and p27(kip1), in parallel to Uchl1, increased in spermatocytes of apoptotic appearances in response to heat-stress, but not in multinucleated giant cells; Jab1 bound to Uchl1 in testis protein extracts, and co-localized with Uchl1 and p27(kip1) specifically in spermatocytes with apoptotic appearances. These results suggest that the accumulation of Uchl1 protein is involved in the heat-stress-induced spermatocyte apoptosis through a new pathway related with Jab1 and p27(kip1), but not the formation of multinucleated giant cells.

Expression and their significance of Jab1 p27kip1 in laryngeal squamous cell carcinoma and Hep-2 cells / 临床耳鼻咽喉头颈外科杂志

OBJECTIVE@#To discuss the expression and the significance of Jab1 p27kip1 in laryngeal squamous cell carcinoma and Hep-2 cells.@*METHOD@#Immunohistochemical method was used to examine the expressions of Jab1 and p27kip1 proteins in 50 cases laryngeal squamous cell carcinomas and 10 cases normal laryngeal tissues adjacent to laryngeal squamous cell carcinoma. Hep-2 cells were transfected with synthetic Jab1 siRNA by Lipofectamine 2000. RT-PCR method was adopted to examine the mRNA expression of the Jab1 and p27kip1 gene in Hep-2 cells which was treated with Jab1 siRNA II.@*RESULT@#Clearly brown staining restricted to nucleus was considered as positive expression of Jab1 and p27kip1 protein. The expression rate of Jab1 protein in laryngeal squamous cell carcinoma was significantly higher than that of normal laryngeal mucosa, and the expression rate of protein p27kip1 in laryngeal squamous cell carcinoma was significantly lower than that of normal laryngeal mucosa. There was a negative relationship between Jab1 and p27kip1 protein in laryngeal squamous cell carcinoma. The expression of Jab1 mRNA was suppressed markedly after transfected by Jab1 siRNA II. As the reaction time increased, the expression of Jab1 mRNA of Hep-2 cells decreased significantly, and the expression of p27kip1 mRNA remained unchanged.@*CONCLUSION@#The expression rate of Jab1 protein in laryngeal squamous cell carcinoma is significantly higher than that of normal laryngeal mucosa. There is a negative relationship between Jab1 and p27kiPl protein in laryngeal squamous cell carcinoma. After transfected by Jab1 siRNA II in the Hep-2 cells, the expression of Jab1 mRNA is suppressed markedly. Jab1 siRNA would be a good methodology for the further study.

Inhibitory effect of Jab1-specific shRNA on the progression of human laryngeal carcinoma xenografts nude mice / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To evaluate the antitumour efficacy of shRNA plasmid specifically targeting Jab1 gene.</p><p><b>METHODS</b>The nude mouse tumor model was made by subcutaneous injection of human laryngeal carcinoma Hep-2 cells. The tumor growth was monitored after intratumoral injection of pJab1, pKB plasmids and saline. Jab1 and p27 expressions in tumour tissues were examined by immunohistochemistry staining and RT-PCR.</p><p><b>RESULTS</b>Mean volume of the pJab1-treated tumors was (267.60 ± 88.19) mm(3), significantly less than that of tumors treated with pKB plasmids (832.20 ± 140.39) mm(3) or saline (895.40 ± 145.93) mm(3) (F = 36.73, P < 0.001). Immunohistochemistry showed that the expression of Jab1 protein was significantly reduced in the pJab1-treated group (32.40% ± 5.59%) compared to the control groups, whereas the expression rate of p27 protein in the pJab1 group (76.80% ± 6.30%) was significantly increased compared to the control groups (P < 0.001). The down regulation of Jab1 protein by pJab1 plasmid was consistent with mRNA expression confirmed by RT-PCR. The level of Jab1 mRNA level in the pJab1-treated group (0.65 ± 0.03) was significantly lower than the control groups (F = 558.00, P < 0.001), however, p27 mRNA, was 0.80 ± 0.02, had no significant alteration (F = 1.52,P > 0.05).</p><p><b>CONCLUSIONS</b>The pJab1 plasmid results in downregulation of Jab1 in an xenograft tumour model of human laryngeal carcinoma Hep-2 cells and significantly inhibits the tumour growth in vivo. This suggests that pJab1 plasmid specifically targeting Jab1 gene expression could be an effective therapy for human laryngeal carcinoma.</p>

CSN1 inhibits c-Jun phosphorylation and down-regulates ectopic expression of JNK1

CSN1 is a component of the COP9 signalosome (CSN), a conserved protein complex with pleiotropic functions in many organs and cell types. CSN regulates ubiquitinproteasome dependent protein degradation via the deneddylation and the associated deubiquitination activities. In addition, CSN associates with protein kinases and modulates cell signaling, particularly the activator protein 1 (AP-1) pathway. We have shown previously that CSN1 suppresses AP-1 transcription activity and inhibits ultraviolet (UV) and serum activation of c-fos expression. Here we show that CSN1 can inhibit phosphorylation of proto-oncogene c-Jun product and repress c-Jun dependent transcription. Further, CSN1 dramatically downregulates ectopic expression of c-Jun N-terminal kinase 1 (JNK1) in cultured cells. The decline in JNK1 is not caused by excessive proteolysis or by 3' UTR-dependent mRNA instability, but by CSN1-dependent repression of one or multiple steps in transcriptional and posttranscriptional mechanisms. Thus, in contrast to CSN5/Jab1, which promotes AP-1 activity, CSN1 displays a negative effect on the AP-1 pathway. Finally, we discuss about the dynamic equilibrium of the CSN complexes in regulation of the AP-1 pathway.

Expression and relationship of p27(kip1) and its related molecules Jab1 and CRM1 during proliferation of lymphoma cells U937 / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the expression and relationship of p27(kip1) and its related molecules Jab1 and CRM1 during proliferation of lymphoma cells U937.</p><p><b>METHODS</b>U937 cells were treated with serum starvation and release, and the effects of these treatments on the cell growth was tested with cell number counting. The expression and localization of p27(kip1), Jab1 and CRM1 in U937 cells were detected by Western blot, double immunolabelling and laser scanning confocal microscopy.</p><p><b>RESULTS</b>The growth of U937 cells was blocked by serum starvation. The total protein of p27(kip1) was increased while Ser10-phosphorylated p27(kip1) -related molecules Jab1 and CRM1 were decreased. Meanwhile, the location of p27(kip1) was changed from cytoplasm into nuclei. After serum release, the location of p27(kip1) expression reappeared in the cytoplasm again.</p><p><b>CONCLUSION</b>During the proliferation process of lymphoma U937 cells, Jab1 and CRM1 may influence the location and expression of p27kip1, and may participate in regulation of growth of NHL cells.</p>

Expression and relationship of p27(kip1) and its nuclear export factor Jab1 in lymphoma cell Jurkat / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the expression and relationship of p27(kip1) and its nuclear export factor Jab1 during proliferation process of lymphoma cell.</p><p><b>METHODS</b>Jurkat and Raji cells were treated with serum starvation and then serum release. The protein and mRNA expression of p27(kip1), Jab1 in the cells were detected by Western blot and RT-PCR respectively. LMB were used for stimulating Jurkat cells during their proliferation process, and then the expression changes of p27(kip1) and Jab1 were detected. An eukaryotic expression plasmid(pcDNA3. 1-myc) containing Jab1 was constructed. Jurkat cell were transfected in vitro with or without pcDNA3. 1-myc-Jab1. Double immunolabelling was used to identify the localization of p27(kip1). Immunoprecipitation was used to detect the combination of p27(kip1) and Jab1.</p><p><b>RESULTS</b>The growth of Jurkat and Raji cells were blocked by serum starvation. The total protein amount of p27(kip1) increased while that of Jab1 decreased. The reverse changes were happened after serum release, but the mRNA expression of p27(kip1) has no significant change. LMB could inhibit the cell proliferation caused by serum release. The expression of p27(kip1) was up-regulated and Jab1 down-regulated when Jurkat cells were treated with LMB. After pcDNA3. 1-myc-Jab1 infected Jurkat cells for 48 h, the distribution of p27(kip1) was translocated from nucleus into cytoplasma. p27(kip1) and Jab1 could form compound in Jurkat and Raji cells detected by Immunoprecipitation.</p><p><b>CONCLUSION</b>Jab1 may influence the location and expression of p27(kip1) through integrating with p27(kip1), and then participates in regulating the growth of NHL cell through interfering with the function of p27(kip1).</p>