人端粒酶逆转录亚单位(hTERT)基因特异性siRNA对MCF-7细胞生长抑制作用的研究

目的 研究人端粒酶逆转录亚单位（hTERT）特异性siRNA对MCF-7细胞体外生长及体内肿瘤形成能力的抑制作用。方法 设计并化学合成针对hTERT的siRNA，用脂质体转染法将其导入MCF-7细胞内，通过软琼脂克隆形成试验及接种裸鼠的肿瘤形成实验，观察hTERT-siRNA对人乳腺癌MCF-7细胞体外及体内的生长抑制作用。结果 软琼脂克隆形成试验显示，hTERT-siRNA转染的MCF-7细胞克隆形成数量明显少于对照组，抑制率达到84．1％。裸鼠体内实验结果显示，hTERT-siRNA转染组肿瘤生长速度也明显慢于对照组。结论 hTERT-siRNA在体内外均显示可以有效、特异地抑制肿瘤细胞的生长。     

小干扰RNA抑制c-Myc表达对MCF-7细胞增殖和凋亡的影响

目的应用小干扰RNA（siRNA）干扰乳腺癌MCF-7细胞的c-Myc表达，了解c-Myc对肿瘤细胞增殖和凋亡的作用。方法将c-Mye siRNA，经IApofectamineTM2000脂质体转染MCF-7细胞后，实时定量RT-PCR和Western Blotting法检测细胞cMyc mRNA和蛋白的表达，MTT法和流式细胞仪检测干扰后细胞的增殖和凋亡水平。结果转染后MCF-7细胞的c-Myc的mRNA与蛋白表达明显减弱，增殖能力显著降低。洲亡率明显提高。结论运用RNAi技术，可以有效地干扰MCF-7细胞c—Myc的表达，抑制细胞增殖，并诱导细胞渊亡。     

Screening of Efficient siRNA Target Sites Directed against Gatekeeper Genes for DNA Repair

DNA double-strand breaks (DSBs) are common le-sions that occur in cells. They are caused by exogenous sources such as ionizing radiation, and by endogenous sources such as radicals generated during metabolic processes[1]. In mammalian cells, DSBs are repaired ei-ther by the homologous recombination (HR) pathways or by the non-homologous end joining (NHEJ)[2] pathways to maintain the fidelity of human genome. The basic mechanism and factor requirements of the two pathways are different. V…     

Bcl-2 siRNA抑制HL-60细胞bcl-2基因表达

目的应用RNA干扰技术观察Bcl2siRNA对白血病细胞HL60中bcl2基因表达的影响,探讨siRNA技术在白血病治疗中的作用。方法利用化学合成法体外化学合成Bcl2siRNA,将Bcl2siRNA与HL60细胞共孵育,用MTT法、荧光染色观察细胞增殖及凋亡情况,用RTPCR检测Bcl2mRNA水平,用荧光染色测Bcl2蛋白水平。结果Bcl2siRNA与HL60细胞共孵育48h后,HL60细胞凋亡率增加,Bcl2mRNA水平下调,Bcl2蛋白表达水平降低。转染GAPDHsiRNA组的细胞对Bcl2表达无影响。结论Bcl2siRNA能够特异性降低Bcl2mRNA水平及蛋白质的表达,促进HL60细胞凋亡。     

Eg5基因在神经母细胞瘤细胞增殖和凋亡中的作用

目的探讨Eg5基因对神经母细胞瘤(NB)细胞增殖和凋亡的影响。方法取2株NB细胞株SHSY-5Y和NBL-S,分别转染针对Eg5基因的小干扰RNA(siRNA),分为细胞对照组(用等体积的水代替siRNA,只含有脂质体,未转染细胞)、siRNA对照组(转染siRNA对照)和siRNA干扰组(转染Eg5 siRNA),每组6孔,每孔1×10~6个细胞。使用实时定量聚合酶链式反应(real-time PCR)检测Eg5 mRNA表达水平的变化;使用5-乙炔基-2’-脱氧尿苷(EdU)掺入实验和克隆形成实验检测下调Eg5表达对NB细胞增殖的影响;使用流式细胞术检测下调Eg5表达对NB细胞凋亡和细胞周期的影响。结果荧光定量PCR检测结果显示,siRNA干扰组Eg5 mRNA表达水平与细胞对照组和siRNA对照组相比显著减少,差异有统计学意义(P<0.05);EdU掺入实验和克隆形成结果表明,siRNA干扰组细胞中DNA的合成量和细胞克隆数量低于细胞对照和siRNA对照组,差异有统计学意义(P<0.05);流式细胞术检测结果显示,细胞对照组和siRNA对照组细胞的凋亡比率低于siRNA干扰组细胞的凋亡比率,差异有统计学意义(P<0.05);细胞周期的检测结果显示,细胞对照组和siRNA对照组细胞中G0/G1期所占比率<50%,而siRNA干扰组细胞中G0/G1期所占比率>70%,差异有统计学意义(P<0.05)。结论在NB细胞中使用siRNA下调Eg5表达,能够抑制NB细胞增殖,促进细胞凋亡。     

Nonsteroidal estrogen receptor isoform‐selective biphenyls

Estrogen receptor (ER) has been a therapeutic target to treat ER‐positive breast cancer, most notably by agents known as selective estrogen receptor modulators (SERMs). However, resistance and severe adverse effects of known drugs gave impetus to the search for newer agents with better therapeutic profile. ERα and ERβ are two isoforms sharing 56% identity and having different physiological functions and expressions in various tissues. Only two residues differ in the active sites of the two isoforms motivating us to design isoform‐selective ligands. Guided by computational docking and molecular dynamics simulations, we have designed, synthesized, and tested, substituted biphenyl‐2,6‐diethanones and their derivatives as potential agents targeting ERα. Four of the molecules synthesized exhibited preferential cytotoxicity in ERα+ cell line (MCF‐7) compared to ERβ+ cell line (MDA‐MB‐231). Molecular dynamics (MD) in combination with molecular mechanics‐generalized Born surface area (MM‐GBSA) methods could account for binding selectivity. Further cotreatment and E‐screen studies with known ER ligands—estradiol (E₂) and tamoxifen (Tam)—indicated isoform‐selective anti‐estrogenicity in ERα+ cell line which might be ER‐mediated. ERα siRNA silencing experiments further confirmed the ER selective nature of ligands.     

Targeting JNK-interacting protein 1 (JIP1) sensitises osteosarcoma to doxorubicin

Osteosarcoma (OS) is the most common primary malignant bone tumour in children and adolescents. Despite aggressive therapy, survival outcomes remain unsatisfactory, especially for patients with metastatic disease or patients with a poor chemotherapy response. Chemoresistance contributes to treatment failure. To increase the efficacy of conventional chemotherapy, essential survival pathways should be targeted concomitantly. Here, we performed a loss-of-function siRNA screen of the human kinome in SaOS-2 cells to identify critical survival kinases after doxorubicin treatment. Gene silencing of JNK-interacting-protein-1 (JIP1) elicited the most potent sensitisation to doxorubicin. This candidate was further explored as potential target for chemosensitisation in OS. A panel of OS cell lines and human primary osteoblasts was examined for sensitisation to doxorubicin using small molecule JIP1-inhibitor BI-78D3. JIP1 expression and JIP1-inhibitor effects on JNK-signalling were investigated by Western blot analysis. JIP1 expression in human OS tumours was assessed by immunohistochemistry on tissue micro arrays. BI-78D3 blocked JNK-signalling and sensitised three out of four tested OS cell lines, but not healthy osteoblasts, to treatment with doxorubicin. Combination treatment increased the induction of apoptosis. JIP1 was found to be expressed in two-thirds of human primary OS tissue samples. Patients with JIP1 positive tumours showed a trend to inferior overall survival. Collectively, JIP1 appears a clinically relevant novel target in OS to enhance the efficacy of doxorubicin treatment by means of RNA interference or pharmacological inhibition.     

Silencing of DNA repair sensitizes pediatric brain tumor cells to γ-irradiation using gold nanoparticles

We present a nanoparticle (NP)-mediated delivery vehicle that effectively carries and protects siRNA in pediatric ependymoma (EP) and medulloblastoma (MB) cells. The delivery vehicle consists of gold NPs coated with a polymeric shell comprising polyethylene glycol (PG), chitosan and polyethyleneimine (Au-CP-PEI). NPs loaded with siRNA knocked down Ape1 expression by over 75% in both MB and EP cells. Further, this reduction in Ape1 expression is associated with an increase in DNA damage after irradiation. The results indicate that NP-associated delivery of siApe1 is a feasible approach to circumventing pediatric brain tumor resistance to radiation therapy.     

Specific knock‐down of tissue non‐specific alkaline phosphatase mRNA levels inhibits intracellular lipid accumulation in 3T3‐L1 and HepG2 cells

The use of non‐specific inhibitors of tissue non‐specific alkaline phosphatase (TNSALP) in pre‐adipocytes blocks intracellular lipid accumulation. TNSALP is also expressed in hepatocytes, which are known to accumulate lipid in a similar manner to pre‐adipocytes. The purpose of this study was to use specific silencing of TNSALP mRNA, using short interfering (si) RNA, to investigate the role of TNSALP in intracellular lipid accumulation in 3T3‐L1 and HepG2 cells. Cellular activity of TNSALP was measured using an automated colorimetric assay, and intracellular lipid accumulation was determined using the lipid‐specific dye, Oil Red O. Cells were transfected with siRNA directed against TNSALP mRNA, and expression of the TNSALP gene was determined at selected time points postinduction of lipid droplet formation. Expression of the TNSALP gene was inhibited by a maximum of 88 ± 1.9% (P < 0.005 vs. control) 11 days after initiation of lipid droplet formation in the 3T3‐L1 cells and 80 ± 8.9% (P < 0.05 vs. control) after 4 days in the HepG2 cells. This led to significant inhibition of both TNSALP activity and intracellular lipid accumulation in both cell lines. These data demonstrates that TNSALP plays an important role in the control of lipid droplet formation in both pre‐adipocyte and hepatocyte cell lines.     

siRNA在卵巢癌靶向治疗中的研究进展

小干扰RNA(siRNA)可以以高度精确的方式诱导基因沉默，因此可用作研究体内和体外单基因功能的工具，也可成为潜在的新靶向治疗药物。卵巢癌是目前最致命的妇科恶性肿瘤，治疗选择有限，需要改进的靶向疗法来对抗卵巢癌。近些年来，siRNA在卵巢癌靶向治疗中的研究越来越受到关注，本文将对siRNA在卵巢癌靶向治疗中的研究进展展开综述。