MEKK3基因siRNA重组腺病毒表达载体的构建及其对胃腺癌AGS细胞MEKK3的表达抑制

目的 构建人MEKK3基因的小干扰RNA(siRNA)重组腺病毒载体表达载体,观察其在胃腺癌AGS细胞中对MEKK3的表达抑制.方法 设计并合成针对人MEKK3基因3个不同部位siRNA靶点的模板DNA序列,以MluⅠ及XhoⅠ克隆入pRNAT-H1.1/Adeno穿梭载体中,得到的质粒用PmeⅠ线性化后在大肠埃项菌BJ5183中与腺病毒骨架质粒pAdEasy-1进行同源重组.卡那霉素筛选后,用PacⅠ酶切鉴定.鉴定正确的质粒经PacⅠ酶切、乙醇沉淀后转染293A细胞,包装得到具有感染能力的pAd-MEKK3-siRNA重组腺病毒.病毒体外转导人胃腺癌AGS细胞,Western印迹法检测其对MEKK3蛋白表达的抑制.结果酶切和测序鉴定表明3个MEKK3 siRNA重组腺病毒表达载体正确无误.Western印迹检测结果显示3个pAd-MEKK3-siRNA重组腺病毒表达载体中有两个可有效地抑制胃腺癌AGS细胞中MEKK3基因的表达,其中以pAd-MEKK3-siRNA3的抑制作用最显著,有效率达89 %.结论 成功构建了针对MEKK3基因的siRNA重组腺病毒载体,为进一步研究MEKK3基因在人胃腺癌AGS细胞中的作用和功能奠定了基础.     

RhoC在胃癌细胞中的表达及其小干扰RNA表达载体的构建与鉴定

目的 :检测RhoC在胃癌细胞系中的表达 ,并构建其小干扰RNA(siRNA)表达载体。方法 :以Westernblot方法检测RhoC在多株胃癌细胞系中的表达。利用计算机辅助设计RhoC特异性siRNA ,体外合成siRNA基因并将其定向克隆入真核表达载体mU6pro。以脂质体法转染RhoC siRNA载体至高转移的人胃癌细胞系AGS中 ,以Westernblot方法鉴定RhoC siRNA对RhoC表达的作用。结果 :RhoC蛋白在具有高转移潜能的胃癌细胞系中表达增强。利用BbsⅠ和XbaⅠ双酶切法鉴定重组载体后 ,DNA测序证实合成的siRNA基因序列正确并已被准确克隆入mU6pro载体。RhoC siRNA载体可特异性抑制AGS细胞中RhoC的表达。结论 :RhoC特异性siRNA表达载体成功构建 ,为后期基因治疗的研究奠定了基础     

siRNA表达载体介导靶向NADH-细胞色素b5还原酶基因的RNA干扰实验研究

目的探索经载体介导的RNA干扰抑制人NADH-细胞色素b5还原酶（bSR）基因表达的可行性。方法应用网络在线软件设计并合成两条针对b5R mRNA的RNA干扰的DNA模板片段，分别将其克隆至经过改建、带有neo基因的pSilencer1．0-U6载体上，构建成siRNA真核表达载体；脂质体转染法将上述重组质粒转入人肺成纤维细胞和BEL-7402肝癌细胞株。通过半定量RT-PCR和荧光定量RT—PCR分析，检测所构建的重组siRNA真核表达载体对b5R基因表达的干扰效应。结果获得两个能在细胞内生成靶向b5R基因siRNA的重组载体pSib5R-1和pSib5R-2；其中pSib5R-2对成纤维细胞b5R mRNA的抑制率达81.7％，对BEL-7402细胞b5R mRNA的抑制率达60％。结论两种细胞b5R基因的表达均可被载体介导的RNA干扰有效抑制；成功构建了针对b5R基因的siRNA表达载体，为建立稳定表达siRNA的、b5R酶缺陷的细胞模型提供了实验基础。     

人防御素-5基因的克隆和真核表达载体的构建

目的对人防御素5(HD-5)基因进行克隆,构建真核表达载体HD5-pPICZαA。方法从人cDNA文库中PCR扩增HD-5基因片段,用EcoRⅠ和XbaⅠ分别双酶切HD-5基因扩增产物和毕赤酵母表达载体pPICZαA,用T4DNA连接酶连接目的基因片段和pPICZαA,然后转化到E.coli Top10中,Zeocin筛选转化子并进行PCR、酶切和序列鉴定。结果提取阳性克隆的重组质粒,EcoR Ⅰ和Xba Ⅰ双酶切后跑电泳获得预期条带;同时重组质粒经序列测定,证实HD-5基因正确插入pPICZαA中,插入位置、方向均正确。结论成功构建人防御素5基因的真核表达载体HD5-pPICZαA,为HD-5蛋白的真核真核表达奠定基础。     

人Qki-5基因重组腺病毒的制备

目的:构建针对Qki-5人重组腺病毒表达载体,并在能在转染该病毒的人乳腺癌细胞株MDA-MB-231中观察到该基因过表达效果.方法:重组腺病毒穿梭载体pShuttle-Qki-5-IRES-EGFP与骨架载体共转化到大肠杆菌BJ5183中,同源重组得到重组腺病毒载体,后者转染HEK293细胞,包装并扩增出病毒颗粒.用获得的病毒感染Qki-5表达较低的人乳腺癌细胞株MDA-MB-231,收集细胞总RNA和总蛋白,采用RT-PCR和Western blot方法检测细胞中基因表达的变化.结果:经限制性内切酶酶切鉴定,证实针对Qki-5基因的重组腺病毒载体构建成功.RT-PCR和Western blot方法证实,在MDA-MB-231细胞中,Qki-5基因在mRNA和蛋白水平均有上升.结论:Qki-5腺病毒载体够建成功并且可以在乳腺癌细胞MDA-MB-231内表达.     

人GDF-5重组腺病毒载体的构建及其在人间充质干细胞中的表达

本研究目的在于构建携带GDF-5基因的重组腺病毒表达载体,并用其感染人骨髓来源的间充质干细胞(MSCs)研究GDF-5的表达。从含有人GDF-5基因核心序列的质粒pCMV-SPORT6上通过PCR扩增GDF-5,将其酶切连接到穿梭质粒pAdtrack-CMV上,在BJ5183中和骨架质粒pAdeasy-1同源重组,筛选阳性克隆并酶切鉴定,线性化后磷酸钙法转染入人胚肾293细胞中包装、扩增,得到含有GDF-5基因的重组腺病毒并测定其滴度。用收集的腺病毒感染靶细胞MSCs,在基因水平检测GDF-5的表达情况。结果表明,成功构建了含有GDF-5基因的重组腺病毒载体,病毒滴度为1×109PFU/ml。重组腺病毒能有效感染MSCs并表达目的基因。通过构建该腺病毒并感染人MSCs可得到能持续一定时间表达GDF-5蛋白的MSCs,为这种转基因的MSCs进一步修复组织奠定了基础。     

GCS通过MEK/ERK通路调控白血病多药耐药细胞凋亡相关基因bcl-2的表达

目的:探讨葡萄糖神经酰胺合成酶(GCS)是否通过MEK/ERK信号通路调控凋亡相关基因bcl-2的表达,从而诱导人白血病K562/A02细胞多药耐药。方法:用小干扰RNA(siRNA)靶向干扰K562/A02细胞中GCS的表达,real-time PCR、Western blotting检测Bcl-2、磷酸化及总ERK水平;用MEK特异性化学抑制剂U0126抑制MEK/ERK信号通路的活化,real-time PCR与Western blotting技术分别检测Bcl-2 mRNA与蛋白水平;CCK-8试剂盒检测细胞存活情况。结果:与阴性对照组比较,GCS siRNA明显抑制K562/A02细胞GCS和Bcl-2的表达,并抑制MEK/ERK信号通路的活化;U0126使Bcl-2 mRNA及蛋白水平呈浓度依赖性下降,并使K562/A02细胞ADM敏感性增加。结论:GCS通过MEK/ERK信号通路调控K562/A02细胞株中凋亡相关基因bcl-2的表达,从而诱导白血病细胞多药耐药。     

抑制RAGE表达的siRNA重组腺病毒载体的构建及鉴定

目的 构建特异性针对细胞膜上晚期糖基化终末产物受体(RAGE)的小干扰RNA(siRNA)腺病毒载体,鉴定其对大鼠胰岛β细胞系INS-1细胞RAGE表达的影响.方法 设计并合成针对大鼠RAGE基因的siRNA的靶DNA序列,克隆于穿梭载体pAdTrack中,与腺病毒骨架质粒pAdeasy-1在BJ5183细菌中进行同源重组,脂质体法转染至QBI293A细胞中包装,获得RAGE-siRNA的重组腺病毒,荧光显微镜观察RAGE-siRNA感染INS-1细胞后绿色荧光蛋白(GFP)的表达,Western印迹检测RAGE的蛋白表达.结果 成功制备RAGE-siRNA重组腺病毒,在INS-1细胞中RAGE-siRNA感染效率达到90 %以上,并能够抑制INS-1细胞RAGE的表达.结论 成功构建了携带RAGE的siRNA重组腺病毒载体,能有效沉默INS-1细胞中RAGE的表达.     

人脂联素基因在昆虫杆状病毒表达系统中的表达

目的利用杆状病毒表达系统探讨人脂联素(ADPN)基因在Sf9昆虫细胞中的高效表达。方法利用PCR方法扩增人脂联素基因,与pFastBac1质粒连接,转化入含有穿梭载体bacmid的大肠杆菌DH10Bac中,筛选发生转座作用的重组穿梭载体Bacmid-ADPN并转染Sf 9昆虫细胞,使其表达重组杆状病毒,经SDS-PAGE、Western blot检测表达产物。结果重组杆状病毒感染的Sf 9细胞形态变化明显,能够表达出与脂联素多克隆抗体相结合的蛋白,蛋白分子质量约为30 ku。结论人脂联素基因在真核细胞中成功得到表达,为进一步研究其生物学活性和作用机制奠定基础。     

利用不同方法检测RNAi抑制人pescadillo基因的表达

目的:构建人pescadillo(PES1)基因siRNA的真核表达载体,观察其对PES1表达的影响。方法:利用RNA干扰(RNAi)技术,设计并合成了2条针对PES1基因的siRNA,将其克隆到siRNA表达载体pSliencer2.1-U6neo上。分别用以下3种方法检测RNAi的抑制效果:(1)将RNAi重组质粒和带FLAG标签的PES1共转染293T人胚肾细胞,用FLAG抗体进行Western blot;(2)将RNAi重组质粒和带GFP标签的PES1共转染293T细胞,用荧光显微镜观察GFP的亮度;(3)在293T细胞中仅转染小干扰RNA(siRNA)重组质粒,用PES1抗体进行Western blot分析。结果:测序证明,成功构建了PES1siRNA真核表达载体。通过Western blot实验证明,构建的siRNA能有效抑制外源性及内源性PES1基因表达;荧光显微镜检查发现siRNA能明显减弱细胞中荧光强度,抑制PES1的表达。结论:成功地构建了PES1siRNA的真核表达载体,利用3种不同方法均证明该siRNA能有效地抑制PES1基因的表达。     

Regulation of c-Fos and Fra-1 by the MEK5-ERK5 pathway

BACKGROUND: ERK5 is the newest subfamily member of the mitogen-activated protein kinase (MAPK) family, and is activated by various extracellular signals including growth factors. MEK5 is a specific activator of ERK5. c-Fos and Fra-1, well-known immediate early gene products, are members of the AP-1 family. We previously reported that activation of the MEK5-ERK5 pathway is able to induce expression of c-Fos. RESULTS: We have found that activation of the MEK5-ERK5 pathway causes the phosphorylation and stabilization of c-Fos and Fra-1. Phosphorylation of c-Fos appears to be mediated by ERK5 and a kinase(s) lying downstream of ERK5, and the MEK5-ERK5 pathway-dependent phosphorylation sites on c-Fos are different from the ERK1/2 pathway-dependent ones. Interestingly, activation of the MEK5-ERK5 pathway, but not that of the ERK1/2 pathway, is found to markedly increase the transactivation activity of c-Fos. Furthermore, our results show that the C-terminal half of ERK5 is necessary for the maximal activation of the transactivation activity of c-Fos and Fra-1. CONCLUSION: These results reveal a role of the MEK5-ERK5 pathway in modulating the function of the Fos family proteins which is different from the role of the ERK1/2 pathway.     

MEK5/ERK5在大鼠脊髓损伤修复过程中表达水平动态变化及临床意义

目的 以大鼠为模型观察脊髓损伤修复过程中MEK5/ERK5(mitogen extracellular signal-regulated kinase 5/extracellular signal kinase 5)表达水平变化及临床指导意义.方法 将成年健康雄性大鼠随机分为实验组和假手术组,应用western-blotting蛋白质印迹技术和Real-Time PCR实时荧光定量检测技术分别检测脊髓损伤后1天,3天,7天,14天后MEK5、ERK5两种蛋白及其mRNA表达水平动态变化情况,通过考察P-ERK(phosphorylated extracellular signal kinase 5)表达水平考察ERK5激活情况.结果 RT-PCR显示实验组组MEK5 mRNA和ERK5 mRNA表达水平均随时间呈逐渐增加的动态变化规律,且与假手术组相比表达水平明显增加;Western blotting显示实验组MEK5表达水平随时间先增加后回落,ERK5表达水平随时间逐渐增加,P-ERK表达水平随时间增加.结论 ERK5表达水平与脊髓损伤修复过程呈正相关,ERK5的促组织细胞分裂增殖的功能可能有助于脊髓损伤加速修复.     

Activation of the MEK5/ERK5 cascade is responsible for biliary dysgenesis in a rat model of Caroli's disease

Polycystic kidney (PCK) rats exhibit a multiorgan cyst pathology similar to human autosomal recessive polycystic kidney disease, and are proposed as an animal model of Caroli's disease with congenital hepatic fibrosis (CHF). This study investigated the expression and function of selected components of the mitogen activated protein kinase (MAPK) pathway in cultured intrahepatic biliary epithelial cells (BECs) of PCK rats. Compared to the proliferative activity of cultured BECs of control rats, those of the PCK rats were hyperresponsive to epidermal growth factor (EGF). The increase in BEC proliferation was accompanied by overexpression of MAPK/extracellular signal-regulated protein kinase (ERK) kinase 5 (MEK5), and subsequent phosphorylation of ERK5 in vitro. The increased proliferative activity was significantly inhibited by the transfection of short interfering RNA against MEK5 mRNA. An EGF receptor tyrosine kinase inhibitor, gefitinib ("Iressa", ZD1839), also significantly inhibited the abnormal growth of cultured BECs of PCK rats. By contrast, treatment with PD98059 and U0126, inhibitors for MEK1/2, was less effective. These results suggest that the activation of the MEK5-ERK5 cascade plays a pivotal role in the biliary dysgenesis of PCK rats, and also provide insights into the pathogenesis of Caroli's disease with CHF. As the MEK5-ERK5 interaction is highly specific, it may represent a potential target of therapy.     

Germline mutations of MEK in cardio-facio-cutaneous syndrome are sensitive to MEK and RAF inhibition: implications for therapeutic options

Cardio-facio-cutaneous (CFC) syndrome is a sporadic developmental disorder characterized by distinctive craniofacial features, heart defects, mental retardation and ectodermal abnormalities. We recently reported missense germline mutations in the genes MEK1 and MEK2 in patients with CFC. These mutations, including F53S and Y130C MEK1, and F57C MEK2, are the first naturally occurring mutations to be identified in these genes. This study reports data concerning the biochemical functions of the novel mutants, as well as the roles of these MEK genes in the MAPK signaling cascade. Our CFC MEK variants cannot induce ERK unless they are phosphorylated by RAF at two key serine residues in the regulatory loop. When we replaced the serine residues with alanines, ERK phosphorylation was significantly reduced in the presence of RAF. We did find that F57C MEK2 activation was less dependent on RAF signaling than the other mutants. This difference results in F57C MEK2 being resistant to the selective RAF inhibitor SB-590885. All three mutants are sensitive to the MEK inhibitor U0126. The majority of CFC cases result from mutations in B-RAF. A recent report indicates the possibility that cancer cells with activated B-RAF have enhanced, selective sensitivity to MEK inhibitors. Thus, regardless of mutations identified in an individual with CFC, MEK inhibition is a potential therapeutic approach for this population.     

HGF mediates cell proliferation of human mesothelioma cells through a PI3K/MEK5/Fra-1 pathway

The ligand hepatocyte growth factor/scatter factor (HGF) and its receptor tyrosine kinase, c-Met, are highly expressed in most human malignant mesotheliomas (MMs) and may contribute to their increased growth and viability. Based upon our observation that RNA silencing of fos-related antigen 1 (Fra-1) inhibited c-met expression in rat mesotheliomas (1), we hypothesized that Fra-1 was a key player in HGF-induced proliferation in human MMs. In three of seven human MM lines evaluated, HGF increased Fra-1 levels and phosphorylation of both extracellular signal-regulated kinase 5 (ERK5) and AKT that were inhibited by the phosphatidylinositol 3-kinase (PI3K) inhibitor, LY290042. HGF-dependent phosphorylation and Fra-1 expression were decreased after knockdown of Fra-1, whereas overexpression of Fra-1 blocked the expression of mitogen/extracellular signal-regulated kinase kinases (MEK)5 at the mRNA and protein levels. Stable MM cell lines using a dnMEK5 showed that basal Fra-1 levels were increased in comparison to empty vector control lines. HGF also caused increased MM cell viability and proliferating cell nuclear antigen (PCNA) expression that were abolished by knockdown of MEK5 or Fra-1. Data suggest that HGF-induced effects in some MM cells are mediated via activation of a novel PI3K/ERK5/Fra-1 feedback pathway that might explain tumor-specific effects of c-Met inhibitors on MM and other tumors.     

A MEK inhibitor abrogates myeloproliferative disease in Kras mutant mice

Chronic and juvenile myelomonocytic leukemias (CMML and JMML) are aggressive myeloproliferative neoplasms that are incurable with conventional chemotherapy. Mutations that deregulate Ras signaling play a central pathogenic role in both disorders, and Mx1-Cre, Kras(LSL-G12D) mice that express the Kras oncogene develop a fatal disease that closely mimics these two leukemias in humans. Activated Ras controls multiple downstream effectors, but the specific pathways that mediate the leukemogenic effects of hyperactive Ras are unknown. We used PD0325901, a highly selective pharmacological inhibitor of mitogen-activated or extracellular signal-regulated protein kinase kinase (MEK), a downstream component of the Ras signaling network, to address how deregulated Raf/MEK/ERK (extracellular signal-regulated kinase) signaling drives neoplasia in Mx1-Cre, Kras(LSL-G12D) mice. PD0325901 treatment induced a rapid and sustained reduction in leukocyte counts, enhanced erythropoiesis, prolonged mouse survival, and corrected the aberrant proliferation and differentiation of bone marrow progenitor cells. These responses were due to direct effects of PD0325901 on Kras mutant cells rather than to stimulation of normal hematopoietic cell proliferation. Consistent with the in vivo response, inhibition of MEK reversed the cytokine hypersensitivity characteristic of Kras(G12D) hematopoietic progenitor cells in vitro. Our data demonstrate that deregulated Raf/MEK/ERK signaling is integral to the growth of Kras-mediated myeloproliferative neoplasms and further suggest that MEK inhibition could be a useful way to ameliorate functional hematologic abnormalities in patients with CMML and JMML.     

Sarcoidosis related to checkpoint and BRAF/MEK inhibitors in melanoma

Therapy for advanced melanoma has deeply changed in the last decade with the introduction of checkpoint and BRAF/MEK inhibitors. Granulomatous reactions have been reported related to these drugs. We performed a systematic review of all the cases described in the medical literature by the search ((“Melanoma”[Mesh]) AND (“Sarcoidosis”[Mesh] OR “Granuloma”[Mesh])). Ninety-one patients under immunotherapy were included in the analyses. The time from the initiation of the immunotherapy until the onset of sarcoidosis or sarcoid-like reaction (SLR) was 7.1 months (SD 9). Peripheral lymph nodes as the mode of onset were seen more frequently in patients under CTLA-4 inhibitors (p = .016) whereas in patients under BRAF/MEK inhibitors used to be in the form of specific skin lesions (p = .006). Chest X-ray stage I-II was the rule in the CTLA-4 and PD-1 groups. On the contrary, stage 0 accounted for 80% of the patients in the BRAF/MEK group examined for pulmonary involvement. Specific skin involvement was the most common manifestation apart from pulmonary involvement. It was more frequent in patients under BRAF/MEK inhibitors and especially in the form of papules. Splenic involvement was found also more frequently in patients under CTLA-4 inhibitors. Specific treatment for sarcoidosis/SLR was prescribed in 50 patients (58.8%), without differences among groups. Almost all patients presented a good prognosis independently of the decision made regarding their previous immunotherapy.ConclusionPhysicians should bear in mind the possibility of sarcoidosis/SLR after the initiation of checkpoint or BRAF/MEK inhibitors in patients diagnosed with advanced melanoma, especially in the form of skin involvement and mediastinal and peripheral lymph nodes. It is important to achieve an accurate diagnosis to rule out the possibility of cancer involvement. What to do with these drugs is yet to be clarified. It seems reasonable to prioritize cancer treatment so it is not mandatory to stop these drugs.