环杷明对马兜铃酸诱导的肾上皮细胞表型转化及Hedgehog通路的影响

目的:探讨环杷明干预Hedgehog(HH)信号对马兜铃酸(AA)致肾小管上皮细胞表型转化和基质累积的影响。方法:根据干预措施将体外培养的大鼠肾小管上皮细胞NRK-52E分为溶剂对照组、AA损伤组(分别用终浓度为1、5和10 mg/L的AA处理细胞)和环杷明干预组(10 mg/L AA基础上加入1、5和10μmol/L环杷明)。细胞培养24 h后,用real-time PCR检测HH信号关键分子Ptch1和Smo、表型转化相关分子α-SMA和E-cadherin、ZO-1、BMP-7和基质成分I型和III型胶原mRNA的表达;ELISA法检测Shh和TGF-β1的含量;细胞免疫荧光染色检测Ptch1、Smo、E-cadherin、α-SMA和III型胶原蛋白表达。结果:AA不仅增加了TGF-β1、α-SMA和III型胶原的表达,降低了E-cadherin和ZO-1的表达,而且诱导了Shh和Smo mRNA表达的升高和Ptch1 mRNA表达的下降,提示AA促进小管上皮细胞表型转化和胶原累积,同时也激活了HH信号通路。环杷明干预AA作用后,Smo mRNA或蛋白表达下调,Ptch1 mRNA表达升高,这说明环杷明抑制了AA诱导的HH信号通路的活化。此外,环杷明也降低TGF-β1、α-SMA、I型和III型胶原的表达,提高BMP-7、ZO-1和E-cadherin的表达,这提示环杷明抑制了AA所致的上皮细胞的表型转化和基质累积。结论:环杷明可抑制AA所致的肾小管上皮细胞表型转化和基质累积,可能是通过靶向抑制HH信号的活化来实现的。     

Galectin-9调控SHH信号通路影响结直肠癌HT29细胞凋亡

目的:探讨半乳糖凝集素9(galectin-9)对结直肠癌细胞凋亡的影响及机制。方法:在结直肠癌细胞系HT29中分别转染galectin-9过表达载体pcDNA3.1-Galectin-9和对照载体pcDNA3.1,用real-time PCR和Western blot检测过表达效果。Annexin V-FITC/PI双染法检测细胞凋亡变化,Western blot测定细胞中活化的caspase-3水平,以及SHH信号通路蛋白Smo、Gli1和SHH的表达变化。用SHH信号通路特异性抑制剂cyclopamine处理上调galectin-9表达的结直肠癌细胞,用上述方法检测细胞凋亡、细胞中活化的caspase-3水平,以及SHH信号通路蛋白Smo、Gli1和SHH的表达变化。结果:pcDNA3.1-Galectin-9可显著上调结直肠癌HT29细胞中galectin-9的mRNA和蛋白水平。上调galectin-9表达后的结直肠癌HT29细胞凋亡率升高,细胞中活化的caspase-3蛋白水平升高,同时细胞中SHH信号通路蛋白Smo、Gli1和SHH的表达水平降低(P0.05)。Cyclopamine处理可以进一步诱导上调galectin-9表达的结直肠癌HT29细胞凋亡,促进细胞中活化的caspase-3蛋白水平上调,降低细胞中SHH信号通路的激活水平(P0.05)。结论:Galectin-9通过抑制SHH信号通路诱导结直肠癌HT29细胞凋亡。     

Carcinogenicity testing of antitumor agents

Carcinogenicity testing of antitumor agents in animal bioassays has been proposed because of the potential for carcinogenicity of this class of agents and the expectation that such testing may indicate prospectively the target organs of any related human oncogenesis. The literature reveals the anticipated confirmations in animals of the carcinogenicity of many antitumor agents. Furthermore, these agents have been associated with human tumors in numerous case reports. Review of the literature also indicates the inability of animal studies to predict the sites of carcinogen-induced tumors in man. The carcinogenic risk assessment of antitumor agents should begin with the determination of the ability of the agent to interact with DNA. Those agents which are capable of alkylating or binding DNA should be tested for mutagenic and teratogenic potential. The presumption of carcinogenicity should be made for DNA-reactive, mutagenic/teratogenic antitumor agents without requiring confirmation in long-term carcinogenicity bioassays in large numbers of animals. The inability of carcinogenicity studies in animals to accurately predict potential human tumor sites must also be recognized.     

沉默Smo基因对人宫颈癌HeLa细胞活力及凋亡的影响

目的:使用RNA干扰技术沉默Smoothened(Smo)基因,探讨其对宫颈癌He La细胞活力和凋亡的影响。方法:采用Smo shRNA转染宫颈癌He La细胞;采用RT-PCR和Western blot技术检测各组He La细胞Smo和转录因子Gli1的mRNA和蛋白表达;采用MTT比色法测定沉默Smo后细胞生长的情况;流式细胞术检测Smo shRNA对细胞周期和凋亡的影响。结果:与对照组比较,Smo shRNA转染细胞72 h后,Smo和Gli1的mRNA和蛋白表达水平均明显降低(P0.05)。Smo基因沉默后,He La细胞的活力明显降低,细胞明显阻滞于G0/G1期,细胞凋亡率显著升高。结论:沉默Smo基因可有效抑制人宫颈癌He La细胞生长,并诱导其凋亡。     

G protein-coupled receptor kinase 2 promotes high-level Hedgehog signaling by regulating the active state of Smo through kinase-dependent and kinase-independent mechanisms in Drosophila

G protein-coupled receptor kinase 2 (Gprk2/GRK2) plays a conserved role in modulating Hedgehog (Hh) pathway activity, but its mechanism of action remains unknown. Here we provide evidence that Gprk2 promotes high-level Hh signaling by regulating Smoothened (Smo) conformation through both kinase-dependent and kinase-independent mechanisms. Gprk2 promotes Smo activation by phosphorylating Smo C-terminal tail (C-tail) at Ser741/Thr742, which is facilitated by PKA and CK1 phosphorylation at adjacent Ser residues. In addition, Gprk2 forms a dimer/oligomer and binds Smo C-tail in a kinase activity-independent manner to stabilize the active Smo conformation, and promotes dimerization/oligomerization of Smo C-tail. Gprk2 expression is induced by Hh signaling, and Gprk2/Smo interaction is facilitated by PKA/CK1-mediated phosphorylation of Smo C-tail. Thus, Gprk2 forms a positive feedback loop and acts downstream from PKA and CK1 to facilitate high-level Hh signaling by promoting the active state of Smo through direct phosphorylation and molecular scaffolding.     

Fused-Costal2 protein complex regulates Hedgehog-induced Smo phosphorylation and cell-surface accumulation

The seven-transmembrane protein Smoothened (Smo) acts as a signal transducer in the Hedgehog (Hh) pathway that mediates many key developmental processes. In Drosophila, Hh-induced phosphorylation promotes Smo cell-surface accumulation and signaling activity; however, the mechanisms controlling Smo phosphorylation and cell-surface accumulation are still unknown. The intracellular signaling complex containing Fused (Fu) and Costal2 (Cos2) is thought to transduce the Hh signal downstream from Smo. Here, we identify a novel feedback mechanism that regulates Smo through the Fu-Cos2 complex. We found that Hh-induced Smo accumulation is inhibited in fu mutant clones or by expressing a dominant-negative form of Fu, and such inhibition is alleviated by removal of Cos2. Conversely, overexpressing Cos2 blocks Smo accumulation, which is reversed by coexpressing Fu. Cos2 blocks Smo accumulation through its C-terminal Smo-interacting domain, and Fu antagonizes Cos2 by phosphorylating Cos2 at Ser572. Furthermore, we found that Ser572 phosphorylation attenuates the Cos2-Smo interaction and promotes Cos2 instability. Finally, we provided evidence that Fu and Cos2 control Smo cell-surface accumulation by regulating Smo phosphorylation. Our data suggest that Cos2-Smo interaction blocks Hh-induced Smo phosphorylation, and that Fu promotes Smo phosphorylation by antagonizing Cos2.     

Ptch和Smo蛋白在非小细胞肺癌中的表达及意义

目的观察非小细胞肺癌(non-small cell lung cancer,NSCLC)及癌旁组织中Ptch和Smo蛋白的表达,探讨Ptch和Smo表达与临床病理学的关系。方法应用免疫组织化学及免疫印迹技术检测NSCLC及癌旁组织中Ptch和Smo蛋白的表达。结果 Ptch和Smo蛋白在癌旁组织中不表达或低表达,但在NSCLC中表达明显增强。Ptch和Smo蛋白的表达与癌组织学分型无关,与癌组织分化程度和淋巴结转移密切相关,分化程度低、淋巴结转移阳性者,表达增强明显。结论过表达的Ptch和Smo蛋白可能参与NSCLC的发生、发展过程。     

干扰维生素D3上调蛋白1通过调控Shh影响高糖诱导的肾小管上皮细胞凋亡

目的:探讨维生素D3上调蛋白1(VDUP-1)对高糖诱导的肾小管上皮细胞凋亡的影响及机制。方法:人近端肾小管上皮HK-2细胞用高糖处理后,real-time PCR和Western blot检测细胞中VDUP-1的水平。HK-2细胞转染VDUP-1小干扰RNA,real-time PCR和Western blot检测抑制效果。高糖条件培养VDUP-1表达下调的HK-2细胞,流式细胞术检测细胞凋亡,试剂盒检测细胞中caspase-3和caspase-9的活性,ELISA法测定培养上清液中肿瘤坏死因子α(TNF-α)含量,Western blot检测细胞中音猬因子(Shh)信号通路关键蛋白Patched 1 (Ptch1)、Smoothened (Smo)、锌指蛋白Gli2和Shh的水平。用外源性Shh处理HK-2细胞,Western blot检测Ptch1、Smo和Gli2的水平。用外源性Shh处理VDUP-1表达下调的HK-2细胞,高糖处理后,流式细胞术检测细胞凋亡,试剂盒检测细胞中caspase-3和caspase-9的活性,ELISA法测定培养液上清中TNF-α含量。结果:高糖处理后,HK-2细胞中VDUP-1的mRNA和蛋白水平升高(P 0. 05)。转染VDUP-1小干扰RNA后,HK-2细胞中VDUP-1的mRNA和蛋白水平下降(P 0. 05)。与正常培养的细胞相比,高糖处理后HK-2细胞凋亡率显著升高,细胞中caspase-3和caspase-9活性明显升高,TNF-α含量亦明显升高(P 0. 05);下调VDUP-1表达后的HK-2细胞经高糖处理后细胞凋亡率显著降低,细胞中caspase-3和caspase-9活性也明显降低(P 0. 05)。高糖培养后细胞中Ptch1、Smo、Gli2和Shh的蛋白水平下降,而下调VDUP-1表达部分拮抗高糖对HK-2细胞中Ptch1、Smo、Gli2和Shh表达的影响。外源性Shh可以促进细胞中Ptch1、Smo和Gli2的表达,抑制高糖诱导的HK-2细胞凋亡和分泌TNF-α,与下调VDUP-1共同抑制高糖诱导的肾小管上皮细胞凋亡。结论:干扰VDUP-1表达可能通过激活Shh信号通路抑制高糖诱导的肾小管上皮细胞凋亡和分泌TNF-α。     

Potentiation of ribavirin-induced teratogenesis by natural purines

Ribavirin, a nucleoside analog, has been shown to possess much promise as an effective antiviral and antitumor agent. In addition, ribavirin has been reported to have significant, reproducible teratogenic activity (Kilham and Ferm, 1977). As the teratogenic effects of certain nucleoside analogs have been found to be altered by natural nucleic acid bases, it was of interest to investigate ribavirin's teratogenic properties in this light. The experiments reported here evaluated the effects of simultaneous administrations of ribavirin and purine nucleic acid bases on developing hamster embryos. The injection of ribavirin-adenine and/or ribavirin-guanine on Day 8 of gestation was observed to significantly increase the percentage of resorbed implantation sites and the percentage of malformed hamster fetuses as compared with the administration of an equivalent dose of ribavirin alone. The anomalies in the hamster fetuses produced by the administration of ribavirin-purine combinations were observed to be generally more severe than anomalies in those fetuses exposed to an equivalent amount of ribavirin alone.     

类风湿关节炎滑膜血管内皮细胞中Smoothened的表达及其意义

 目的:初步观察Sonic Hedgehog信号通路分子Smoothened（Smo）在类风湿关节炎（rheumatoid arthritis, RA）滑膜血管内皮细胞的表达及其生物学意义。方法:收集4例病情中度活动的RA患者的滑膜组织,同时收集4例外伤或半月板损伤（无关节炎）者滑膜组织作为对照组,免疫组化检测滑膜组织Smo蛋白表达情况。采用人脐静脉内皮细胞系EA.hy926作为滑膜血管内皮细胞的模型,予不同浓度肿瘤坏死因子α（TNF-α）处理,Western blotting检测Smo蛋白表达;采用RNAi技术转染体外合成的特异性Smo-siRNA,应用Western blotting检测沉默效果;转染siRNA 24 h后,经TNF-α/放线菌素D（actinomycin D, ActD）诱导细胞凋亡,CCK-8法检测细胞存活率,流式细胞术检测细胞凋亡情况。结果:RA患者滑膜组织Smo表达高于对照组,以血管内皮细胞表达尤为明显。EA.hy926细胞经TNF-α刺激后,Smo蛋白表达上调（P<0.05）。RNA干扰EA.hy926细胞Smo表达后,细胞存活率为（24.30±0.45）%,低于阴性对照组的（36.86±0.62）%（P<0.05）,细胞凋亡率为（48.00±1.96）%,高于阴性对照组的（31.70±0.82）%（P<0.05）。结论: Smo可能参与了RA患者滑膜组织血管内皮细胞凋亡的调控。     

Smoothened transduces Hedgehog signal by physically interacting with Costal2/Fused complex through its C-terminal tail

The Hedgehog (Hh) family of secreted proteins controls many aspects of growth and patterning in animal development. The seven-transmembrane protein Smoothened (Smo) transduces the Hh signal in both vertebrates and invertebrates; however, the mechanism of its action remains unknown. We found that Smo lacking its C-terminal tail (C-tail) is inactive, whereas membrane-tethered Smo C-tail has constitutive albeit low levels of Hh signaling activity. Smo physically interacts with Costal2 (Cos2) and Fused (Fu) through its C-tail. Deletion of the Cos2/Fu-binding domain from Smo abolishes its signaling activity. Moreover, overexpressing Cos2 mutants that fail to bind Fu and Ci but retain Smo-binding activity blocks Hh signaling. Taken together, our results suggest that Smo transduces the Hh signal by physically interacting with the Cos2/Fu protein complex.     

Effect of the Hedgehog-inhibitor cyclopamine on mice with osteosarcoma pulmonary metastases

Chemoresistant metastases of osteosarcoma in humans limit survival in approximately one third of patients. Furthermore, aggressive chemotherapy can lead to side effects and occurrence of secondary malignancies in long time survivors. Therefore, supplemental medical strategies are worthwhile. The well-directed manipulation of cancer-signaling-cascades is an appealing approach. Targeting of the Hedgehog-pathway in cancer has led to promising results in vitro as well as in vivo in a number of different tumor types. Recently, the impact of cyclopamine, which inhibits Hedgehog signaling by binding to the receptor Smoothened, was shown in different human osteosarcoma cell lines in vitro and in vivo. In the present study we examined the influence of cyclopamine on early pulmonary metastases in vivo. Murine osteosarcoma cells, OS-50, were injected into the lateral tail vein of young BALB/c mice. Treatment with subcutaneous cyclopamine injections began after three days. Two weeks later, the animals were sacrificed and the number of pulmonary metastases was counted. We could observe a trend towards decreased metastases in the cyclopamine group (~20%). On the other hand, remarkable side effects were caused by the cyclopamine/ethanol/triolein preparation (mainly skin ulcerations).     

Hedgehog信号通路抑制剂对肝内胆管癌RBE细胞生物学行为的影响

 目的: 研究Hedgehog(Hh)信号通路特异性抑制剂环杷明(cyclopamine)对人肝内胆管癌细胞株RBE生物学行为的影响。方法: 用台盼蓝染色计数法和MTT比色法检测环杷明对RBE细胞增殖的影响;流式细胞术检测凋亡率,Transwell检测环杷明处理前后RBE细胞侵袭能力的变化,Western blot检测环杷明处理前后RBE细胞中Gli1和MMP-9的蛋白表达变化。结果: 环杷明对RBE细胞株增殖的抑制作用呈剂量和时间依赖性。环杷明作用细胞24 h、48 h、72 h后,RBE细胞凋亡率逐渐升高,明显高于对照组的凋亡率。Transwell检测对照组穿透细胞数为154.52±13.61,而实验组穿透数为62.00±12.17,侵袭能力明显下降(P<0.01)。Gli1和MMP-9蛋白均在RBE细胞中表达,环杷明下调RBE细胞的Gli1和MMP-9表达。结论: 阻断Hh信号通路能抑制RBE细胞的增殖,促进其凋亡,并抑制其侵袭能力。     

A direct requirement for Hedgehog signaling for normal specification of all ventral progenitor domains in the presumptive mammalian spinal cord

The hedgehog signaling pathway organizes the developing ventral neural tube by establishing distinct neural progenitor fates along the dorsoventral axis. Smoothened (Smo) is essential for all Hedgehog (Hh) signaling, and genetic inactivation of Smo cells autonomously blocks the ability of cells to transduce the Hh signal. Using a chimeric approach, we examined the behavior of Smo null mutant neural progenitor cells in the developing vertebrate spinal cord, and we show that direct Hh signaling is essential for the specification of all ventral progenitor populations. Further, Hh signaling extends into the dorsal half of the spinal cord including the intermediate Dbx expression domain. Surprisingly, in the absence of Sonic hedgehog (Shh), we observe the presence of a Smo-dependent Hh signaling activity operating in the ventral half of the spinal cord that most likely reflects Indian hedgehog (Ihh) signaling originating from the underlying gut endoderm. Comparative studies of Shh, Smo, and Gli3 single and compound mutants reveal that Hh signaling acts in part to specify neural cell identity by counteracting the repressive action of Gli3 on p0, p1, p2, and pMN formation. However, whereas these cell identities are restored in Gli3/Smo compound mutants, correct stratification of the rescued ventral cell types is lost. Thus, Hh signaling is essential for organizing ventral cell pattern, possibly through the control of differential cell affinities.