The purpose of the present study is to explore the mechanism of IL-12-induced nuclear import of signal transducer and activator of transcription 4 (STAT4). Assayed by analyses of homology alignment of STATs, amino acids 395-416 in DNA binding domain was found to be a potential dimer-specific nuclear localization signal (dsNLS) of STAT4. Therefore, several plasmids were constructed. Wild-type STAT4 was inserted into the SalI and BamHI sites of pEGFP-C1 for the construction of plasmid pEGFP-STAT4. The DNA fragment of STAT4 with the deletion of amino acids 395-416 was amplified by RCR and introduced into the SalI and BamHI sites of pEGFP-C1 which was named pEGFP-STAT4-Del. Classic NLS DNA sequence of SV40 T antigen was inserted into the XhoI and HindIII sites of pEGFP-C1. This plasmid was named as pEGFP-NLS and used as a positive control. Plasmid pEGFP-NLS-STAT4-Del was constructed by inserting STAT4-Del into SalI and BamHI sites of pEGFP-NLS. These plasmids were transiently transfected into Caski cells, respectively. The results showed that, after these transfected cells were stimulated by IL-12, wild type STAT4 existed in the cytoplasm at 0 min, and was predominantly localized to the nucleus at 45 min, and distributed in both cytoplasm and nucleus at 60 min, suggesting that STAT4 translocates from cytoplasm into nucleus and finally re-entries into the cytoplasm during the stimulation of IL-12. However, deletion mutant of STAT4 was arrested in cytoplasm during the IL-12 stimulation. Leptomycin B, which specifically blocks protein export from nucleus into cytoplasm, was used to further demonstrate whether STAT4-Del is transferred into nucleus even with stimulation of IL-12. After the transfected cells were pre-treated by leptomycin B, the wild type STAT4 was mainly localized in nucleus after the IL-12 stimulation, suggesting that STAT4 was translocated from cytoplasm into nucleus by the stimulation of IL-12. On the other hand, the deletion mutant of STAT4 distributed in cytoplasm throughout, implying that the mutant STAT4 lacking of amino acids 395-416 cannot move into nucleus. Furthermore, the insertion of classic NLS into EGFP-STAT4-Del restored nuclear import of STAT4-Del. These results suggest the amino acids 395-416 is a dsNLS mediating IL-12-stimulated nuclear import of activated STAT4.

Recently it was reported that signal transducer and activator of transcription 2(STAT2) involves in carcinogenesis. Previous study showed that several kinds of tumor tissues as well as tumor cell lines highly expressed STAT2. Therefore,in order to further explore the effects of STAT2 on carcinogenesis,STAT2 expression level in cervical cancer cell line HeLa was decreased by using RNA silencing assay.Assayed by XTT,colony formation in soft agar and tumor formation in nude mice.It was demonstrated that STAT2 gene silencing inhibits tumor cell growth in vitro and in vivo, suggesting that STAT2 promotes cell proliferation.

Objective To explore the effect of RNA interference (RNAi) targeting protein kinase C iota (PKCι) on proliferation and apoptosis of cervical carcinoma cell line HeLa. Methods Stable cell lines which were transfected with PKCι shRNA or vector-mock plasmids were established. The cell lines, psi-PKCiota-HeLa, psi-mock-HeLa and HeLa, were used to detect methyl thiazol tetrazolium (MTT) absorbance at 1st-5th day. The cells were cultured in 6-well plates and stained by crystal violent at 21st day, and the stained cells colonies were counted. Flow cytometry was used to detect apoptosis and cell cycle distribution after HeLa cells were transiently transfected with PKC iota shRNA at 72nd h. Results Compared with the psi-mock and blank controls, the transfected cells stably expressing PKCι shRNA showed markedly decrease of proliferation assayed by MTT and plate colony formation. The apoptosis rate of cells transiently transfected with PKCι shRNA (9.54±0.55)% was higher than that of cells transiently transfected with psi-mock (1.31±0.10)% or HeLa blank control cells (2.75±0.24)% (P<0.05). The cells transiently transfected by PKCι shRNA were arrested in G0/G1 phase. Conclusion PKCι is essential for maintaining of HeLa cell proliferation. Silencing PKCι can inhibit the growth of HeLa cells and induce apoptosis.

目前人们认为肿瘤既是遗传性疾病,也可能是免疫学疾病。因此深入探讨肿瘤发生发展与免疫系统的相互关系,才有可能产生更多新策略对肿瘤进行免疫治疗。文章简述肿瘤与免疫系统相互关系,介绍肿瘤逃避免疫应答机制的最新研究进展,并就新近肿瘤免疫治疗策略进行综述。

By way of material consultation,inrestigation and mathmatical statistics,The authors have inrestigated and andalyzed the sport consumption in badminton stadiums in Chenzhou city and get the conclusions;The consumers are mainly people between 20 and 45 years old and with comparatively high schooling.Health building is their first motive.Being lack of hobbies and free time,they don't have regular time,style in badminton stadiums.So some effective measures should be taken to promote the development.

In this paper,an efficient admission control algorithm is proposed to provide different levels of services based on the server workload characteristics.Service quality is ensured by periodical allocation of system resources based on the estimation of request rate and service requirements of prioritized tasks.Admission of lower priority tasks is restricted during high load periods to prevent denial-of-services to high priority tasks.Response delays of the high priority tasks are bounded by the length of the prediction period.

通过对中专学生进行的体质状况跟踪调查分析表明,体育锻炼对学生身体、生理机能的影响很大.各级各类学校应加强在校学生体育锻炼习惯的培养教育,使学生养成一个良好的体育锻炼习惯.