去氢表雄酮通过调节丝/苏氨酸蛋白激酶信号传导通路抑制大鼠Morris肝细胞瘤生长

Objective To investigate the inhibitory effect of dehydroepaimdrosterone(DHEA)on the growth of transplatnted MorriS hepatomas(7288CTC)in vivo in rats.Methods 21 Buffalo rats were randomly devided into 4 groups,including one blank control group(n=5),one group for tumor-bearing control(n=6),and 2 experimental groups with DHEA(n=6)or DHEA-s(n=4).DHEA or DHEA-s was fed to the rats for 4 weeks immediately after Morris hepatomas(7288CTC)was implanted in both flanks.Phenotypes of the spleen lymphocytes were examined by flow cytometry,Akt and PTEN expression in rumor cells was detected by Western blot and immunohistochemistry.Results Tumor weights of DHEA treated group were less than those of the control(P＜0.05),the inhibitory rate was 43%.The results of Western blot and immunohistochemistry showed that in DHEA tumor group,the expression of phosphorilated Akt protein was decreased,the expression of PTEN was enhanced,the percentage of CD3 positive cells and the ratio of CD4/CD8 were increased (P＜0.05). Conclusion DHEA can inhibit tumor growth,possibly via the inhibition of the Akt signaling pathway as well as modulating the immune function.     

P13K/AKt信号通路与肝细胞癌

P13K/AKt信号通路与人类肿瘤的发生、发展密切相关.近年来研究表明,肝细胞癌(HCC)中存在P13K/AKt信号通路异常.此文就P13K/AKt信号通路的构成、转导途径及其在HCC中的作用作一综述.     

PI3K/AKt信号通路与肝细胞癌

PI3K/AKt信号通路与人类肿瘤的发生、发展密切相关。近年来研究表明,肝细胞癌(HCC)中存在PI3K/AKt信号通路异常。此文就PI3K/AKt信号通路的构成、转导途径及其在HCC中的作用作一综述。     

Akt/PKB信号转导通路与脑缺血

Akt被生长因子介导的受体酪氨酸激酶磷酸化激活后可激活一系列底物分子,包括Forkhead转录因子等,对细胞生存和死亡进行调控.随着脑缺血后Akt磷酸化水平(Ser473)的改变,其上游、下游蛋白磷酸化水平也发生变化.预处理可能通过改变Akt蛋白磷酸化水平而产生缺血耐受.Akt/PKB信号转导通路功能障碍可能介导了脑缺血后神经元死亡.     

Ras/ERK信号转导通路在肝纤维化发生发展中的作用

在肝纤维化的发病机制中,肝星状细胞（HSC）发挥关键的作用。各种细胞因子的分泌,引起胞外信息变化。细胞因子与HSC上的相应受体结合,激活多条信号转导通路,将胞外信息转导入核,调控基因的转录和表达,从而引起胶原分泌增多、细胞基质降解和沉积失衡。在参与肝纤维化发生发展的信号转导通路中,Ras/ERK信号转导通路介导的信号转导促使了肝纤维化的发生发展。     

阿霉素诱导磷脂酰肌醇3''''-激酶丝氨酸/苏氨酸蛋白激酶FKHRL1通路对胃癌细胞化疗耐药性的影响

目的探讨阿霉素在胃癌细胞中诱导PI3'K/Akt/FKHRL1通路的激活,对胃癌细胞SGC-7901化疗效果的影响及两者的关系.方法 2004-01～2005-09武汉大学人民医院消化内科采用MTT比色法检测胃癌细胞的生存率,Western印迹法检测FKHRL1磷酸化表达水平,同时观察PI3'K/Akt抑制剂wortmannin对阿霉素诱导的上述变化的影响.结果阿霉素抑制胃癌细胞SGC-7901的生长,呈时间依赖性的诱导FKHRL1磷酸化.wortmannin可明显增强阿霉素的细胞生长抑制作用,同时下调阿霉素诱导的磷酸化FKHRL1表达.结论阿霉素可能是通过激活SGC-7901细胞的PI3′K/Akt通路,呈时间依赖性诱导FKHRL1磷酸化,从而影响胃癌细胞的化疗耐药性.wortmannin可以阻断PI3'K/Akt/FKHRL1通路而提高胃癌的化疗敏感性.     

阿霉素诱导磷脂酰肌醇3′-激酶 丝氨酸／苏氨酸蛋白激酶FKHRL1通路对胃癌细胞化疗耐药性的影响

目的探讨阿霉素在胃癌细胞中诱导PI3′K／Akt／FKHRL1通路的激活，对胃癌细胞SGC-7901化疗效果的影响及两者的关系。方法2004-01-2005-09武汉大学人民医院消化内科采用MTT比色法检测胃癌细胞的生存率，Western印迹法检测FKHRL1磷酸化表达水平，同时观察PI3′K／Akt抑制剂wortmannin对阿霉素诱导的上述变化的影响。结果阿霉素抑制胃癌细胞SGC-7901的生长，呈时间依赖性的诱导FKHRL1磷酸化。wortmannin可明显增强阿霉素的细胞生长抑制作用，同时下调阿霉素诱导的磷酸化FKHRL1表达。结论阿霉素可能是通过激活SGC-7901细胞的PI3′K／Akt通路，呈时间依赖性诱导FKHRL1磷酸化。从而影响胃癌细胞的化疗耐药性。wortmannin可以阻断PI3′K／Akt／FKHRL1通路而提高胃癌的化疗敏感性。     

阿霉素诱导磷脂酰肌醇3′-激酶丝氨酸/苏氨酸蛋白激酶FKHRL1通路对胃癌细胞化疗耐药性的影响

目的探讨阿霉素在胃癌细胞中诱导PI3′K/Akt/FKHRL1通路的激活,对胃癌细胞SGC-7901化疗效果的影响及两者的关系。方法2004-01~2005-09武汉大学人民医院消化内科采用MTT比色法检测胃癌细胞的生存率,Western印迹法检测FKHRL1磷酸化表达水平,同时观察PI3′K/Akt抑制剂wortmannin对阿霉素诱导的上述变化的影响。结果阿霉素抑制胃癌细胞SGC-7901的生长,呈时间依赖性的诱导FKHRL1磷酸化。wortmannin可明显增强阿霉素的细胞生长抑制作用,同时下调阿霉素诱导的磷酸化FKHRL1表达。结论阿霉素可能是通过激活SGC-7901细胞的PI3′K/Akt通路,呈时间依赖性诱导FKHRL1磷酸化,从而影响胃癌细胞的化疗耐药性。wortmannin可以阻断PI3′K/Akt/FKHRL1通路而提高胃癌的化疗敏感性。     

磷酯酰肌醇-3-激酶、丝氨酸／苏氨酸蛋白激酶在2型糖尿病大鼠骨组织中的表达及意义

目的探讨磷酯酰肌醇-3-激酶（P13K）、丝氨酸／苏氨酸蛋白激酶（Akt）在糖尿病大鼠骨组织中的表达及意义。方法将50只体重180—200g的6月龄雌性Wistar大鼠按随机数字表法分为对照组（n=24）和2型糖尿病组（n=26）。2型糖尿病组大鼠予高糖高脂饮食喂养8周后,腹腔注射链脲佐菌素30mg／kg,对照组大鼠正常饮食。糖尿病成模后12周两组大鼠分别行腰椎骨密度测定;应用逆转录聚合酶链反应（RT—PCR）法检测骨组织P13K、Aktl和Akt2mRNA的相对表达。组间比较采用t检验。结果对照组大鼠骨密度高于糖尿病组,差异有统计学意义[（0．079±0．034）比（0．060±0．017）g／cm2,t=2．499,P〈0．05];同时,对照组大鼠骨组织P13K、Aktl、Akt2mRNA均高于糖尿病组（分别为：0．65±0．05比0．51±0．04、0．756±O．031比0．694±0．017、0．77±0．04比0．66±0．04）,差异均有统计学意义（t=4．969、3．924、4．515,均P〈0．01）。结论2型糖尿病大鼠骨组织P13K、Aktl及Akt2表达低于正常,这可能是2型糖尿病骨质疏松发生的分子生物学机制之一。     

正常肝组织和肝癌组织中Pim-2基因的表达

肝癌(HCC)的发生、发展与细胞凋亡有着密切的关系,肝细胞的凋亡受到多种基因、转录因子,生长因子、细胞因子和激素的调节[1].Pim-2基因是丝氨酸苏氨酸激酶Pim家族成员之一,属于一种钙/钙调蛋白调节激酶,在多种细胞组织的进化过程中高度保守,可通过磷酸化底物发挥抗凋亡,促进细胞维持自我生存作用[2].     

L-精氨酸对糖尿病大鼠NO-cGMP信号通路的影响

目的探讨L-精氨酸（Arg）对糖尿病（DM）大鼠一氧化氮（NO）-环磷酸鸟苷（cGMP）信号通路的调控作用。方法给大鼠腹腔注射链脲佐菌素制备DM模型，随机分为DM组、L—Arg治疗组及正常对照组；用药12W末处死大鼠，测定3组大鼠血糖、胰岛素含量以及血浆、心肌、肾脏、睾丸组织中NO、cGMP含量和NOS活性。结果DM组大鼠血糖含量较正常对照组显著升高（P〈0．01），而胰岛素水平（P〈0．01）及血浆、心肌、肾脏、睾丸组织NO水平（分别P〈0．01，P〈0．05，P〈0．05，P〈0．01）和血浆、心肌、睾丸组织cGMP含量（分别P〈0．01，P〈0．01，P〈0．05）及血浆、肾脏、睾丸组织一氧化氮合酶（NOS）活性（分别P〈0．01，P〈0．01，P〈0．05）均较正常对照组明显降低；L—Arg可明显降低DM大鼠血糖水平（P〈0．01），增加胰岛素含量（P〈0.01），同时显著增加血浆、心肌、肾脏、睾丸组织NO水平和血浆、心肌、睾丸组织cGMP含量及血浆、睾丸组织NOS活性（均P〈0．01）。结论DM大鼠NO-cGMP信号通路存在缺陷，L—Arg对DM大鼠NO—cGMP信号通路具有调控作用。     

Inhibition of the growth of Morris hepatoma No. 44 in rats after induction of hypothyroidism: evidence that Morris hepatomas are thyroid dependent.

The growth rate of Morris Hepatoma No. 44 (generation time, 6 mo) was inhibited after the induction of hypothyroidism by Propylthiouracil (PTU) (0.1% in Purina Chow), I131 (1 mCi/100 g body wt i.p.), or surgical thyroidectomy. After 11 wk of treatment, hepatoma weight was 66%, 87%, and 75% (after correction for total body wt) relative to controls in PTU-fed, I131 injected, and thyroidectomized rats, respectively. In each case, exogenous thyroxine (T4) (8 microgram/kg body wt i.p.) reversed these inhibitory effects, while T4 administered to euthyroid rats stimulated hepatoma growth. The degree of growth-inhibition achieved with PTU was not observed in pair-fed rats. In addition, after correction for differences in body weight, the sex of the tumor-bearing rats did not influence the response to PTU. Pretreatment with PTU for 2 wk before implantation did not give any added advantage over the effects of PTU administered approximately 10 days after implantation. Serum levels of triiodothyronine (T3) and T4, as well as the concentration of various biochemic parameters, were determined at the time of death. These results suggest that the growth rate of Morris Hepatoma No. 44 is thyroid hormone dependent.     

Gamma-glutamyltransferase in Morris hepatomas 5123D passaged in Buffalo and in F1 (Buffalo x Wistar) rats

Comparative biochemical and immunological investigations were performed on purified gamma-glutamyltransferase from the Morris hepatoma 5123D and from the 5123D/AS variant passaged in F1 (Buffalo x Wistar) rats. The enzyme was also localized in hepatoma sections by immunofluorescent technique. The obtained results confirm the hypothesis that low gamma-glutamyltransferase activity in Morris hepatoma 5123D/AS is caused by the enzymatic protein defficiency and not by the inhibition of the enzyme.     

环磷酸腺苷-蛋白酶A信号系统参与神经生长因子促进脑缺血再灌注大鼠轴突再生

目的观察脑室注射神经生长因子(NGF)对脑缺血再灌注大鼠神经再生的影响及其与环磷酸腺苷-蛋白激酶A(cAMP-PKA)信号途径的关系。方法采用线栓法制作大鼠脑缺血再灌注模型,将60只大鼠分为假手术组(对照组),单纯脑缺血再灌注组(缺血组),NGF1组,NGF2组(脑缺血再灌注并脑室注射NGF,分别注入0.5及2.5μg/100 g体重)。用放免法检测缺血周边区脑组织cAMP的含量,逆转录聚合酶链反应的方法检测生长相关蛋白43(GAP-43)及蛋白激酶A(PKA)mRNA的表达。结果缺血组6、24 h cAMP的含量下降,GAP-43及PKA mRNA表达减少,NGF治疗组脑组织GAP-43 mRNA表达较缺血组增加,且这种变化与cAMP的含量及PKA mRNA表达增加相一致,并呈剂量依赖性。结论NGF能够促进脑缺血再灌注后的轴突再生,cAMP-PKA信号途径在这个过程中起重要作用。     

肺癌中PI3K／AKT信号通路对Skp2调控机制的研究

目的探讨肺癌中磷脂酰肌醇-3-激酶（P13K）／AKT信号通路对S期激酶相关蛋白2（Skp2）的调控机制。方法体外培养4种类型肺癌细胞系H460、LK2、H446和A549,经LY294002处理细胞24h后实时RT—PCR法检测Skp2基因表达变化;Westernblot检测E2F1蛋白表达变化。结果实时RT—PCR显示LY294002作用后4种肺肿瘤细胞系中skp2基因表达均下降;Westernblot结果表明在小细胞肺癌、肺鳞癌、大细胞肺癌中E2F1蛋白表达降低,肺腺癌中E2F1蛋白未表达。结论肺癌中P13K／AKT通路可在转录水平调节Skp2表达,在小细胞肺癌、肺鳞癌、大细胞肺癌中此种调节可能通过转录因子E2F1发挥作用,而肺腺癌中E2F1不参与此种调节。     

肾透明细胞癌组织中AKT／mTOR的表达变化及意义

目的观察磷酸化蛋白激酶B（p-AKT）和磷酸化哺乳动物雷帕霉素靶蛋白（p-mTOR）因子在肾透明细胞癌组织中的表达变化,为mTOR及AKT抑制剂应用于肾透明细胞癌的治疗提供依据。方法用免疫组化染色测定肾透明细胞癌和正常肾组织中p-AKT和p-mTOR的表达情况。结果p-AKT在肾透明细胞癌和正常肾组织中的阳性表达率分别为61．3％、26．1％（P〈0．01）,p-mTOR的阳性表达率分别为56．0％、28．3％（P〈0．05）。P—AKT表达与肿瘤临床分期明显相关,临床分期越高,其阳性表达率越高（P〈0．05）。p-mTOR蛋白表达与肿瘤临床分期也具有相关性（P〈0．05）。肾透明细胞癌组织中p-AKT与p-mTOR的表达呈正相关（r=0．953,P=0．000）。结论AKT／mTOR信号通路在肾透明细胞癌组织中被过度激活。理论上,应用mTOR及AKT抑制剂可治疗肾透明细胞癌。     

CNP signal pathway up-regulated in rectum of depressed rats and the interventional effect of Xiaoyaosan

AIM:To investigate the distribution and expressionof C-type natriuretic peptide(CNP)/natriuretic peptide receptor B(NPR-B) in the rectum of a rodent depression model and the interventional effect of Xiaoyaosan(XYS).METHODS:Male rats(n = 45) of clean grade(200 ± 20 g) were divided into five groups after one week of adaptive feeding:primary control,depression model,low dose XYS,middle dose XYS,and high dose XYS.The animal experiment continued for 3 wk.Primary controls were fed normally ad libitum.The rats of all other groups were raised in solitary and exposed to classic chronic mild unpredictable stimulation each day.XYS groups were perfused intragastrically with low dose,middle dose,and high dose XYS one hour before stimulation.Primary control and depression model groups were perfused intragastrically with normal saline under similar conditions as the XYS groups.Three weeks later,all rats were sacrificed,and the expression levels of CNP and NPR-B in rectum tissues were analyzed by immunohistochemistry,real-time polymerase chain reaction,and Western blotting.RESULTS:CNP and NPR-B were both expressed in the rectum tissues of all rats.However,the expression levels of CNP and NPR-B at both gene and protein levels in the depression model group were significantly higher when compared to the primary control group(n = 9; P 0.01).XYS intervention markedly inhibited the expression levels of CNP and NPR-B in depressed rats.The expression levels of CNP and NPR-B in the high dose XYS group did not significantly differ from the expression levels in the primary control group.Additionally,the high and middle dose XYS groups(but not the low dose group) significantly exhibited lower CNP and NPR-B expression levels in the rectum tissues of the respectively treated rats compared to the untreated depression model cohort(n = 9; P 0.01).CONCLUSION:The CNP/NPR-B pathway is upregulated in the rectum of depressed rats and may be one mechanism for depression-associated digestive disorders.XYS antagonizes this pathway at least partially.     

miR-21/PTEN/Akt参与白藜芦醇促EPC的体外成血管能力

目的 探讨miR-21及其下游PTEN/Akt信号通路在白藜芦醇促进大鼠骨髓源性内皮祖细胞(EPC)体外成血管能力中的作用.方法 采用密度梯度离心法分离大鼠四肢骨髓的单个核细胞,培养于含10％胎牛血清的EGM-2MV完全培养基中诱导分化成EPC,实验用3～5代的EPC.白藜芦醇(20 μmol/L)干预12 h后,采用...