小鼠IL-18基因修饰瘤苗的抗白血病作用研究

我们在前期工作中成功制备了IL-18基因修饰的白血病疫苗,为了探讨IL-18基因修饰瘤苗的体内抗白血病作用,实验采用L1210小鼠淋巴细胞白血病模型,在小鼠体内接种IL-18基因修饰瘤苗,观察瘤苗对L1210细胞致瘤性的影响及免疫保护作用,并进一步对其抗白血病作用机制进行了探索。结果显示,IL-18基因修饰瘤苗能够明显延长荷瘤小鼠存活时间,大部分小鼠达到长期生存,且长生存小鼠用野生型L1210细胞二次攻击后大多数仍能长期生存,表明IL-18基因修饰瘤苗有显著的抗白血病作用,并可诱导小鼠产生免疫记忆和免疫保护。机制探讨发现,接种IL-18基因修饰瘤苗后,小鼠脾脏淋巴细胞对L1210肿瘤细胞的CTL及NK细胞杀伤活性明显高于对照组(P<0.05),提示IL-18基因修饰瘤苗能够显著增强抗肿瘤CTL和NK细胞反应。接种瘤苗可使小鼠IFN-γ水平升高,但与对照相比无统计学意义,提示IFN-γ可能在IL-18基因修饰瘤苗诱导的抗肿瘤免疫应答中作用不大。     

B7—1基因修饰的肿瘤细胞疫苗抗肿瘤的实验研究

目的：研究B7-1基因修饰的肿瘤细胞作为瘤苗的抗肿瘤作用。方法：通过逆转录病毒载体。将小鼠B7-1基因导入EL-4淋巴瘤细胞中,研究EL-4/B7-1在同系C57BL/6小鼠中的成瘤性及其诱导抗肿瘤免疫的效果。结果：转B7-1基因诱导了CD80的高表达,EL-4/B7-1细胞在小鼠中的成瘤性下降,在肿瘤生长的早期对实验性荷瘤小鼠进行治疗。基因修饰的瘤苗作用明显增强,EL-4/B7-1细胞能有效地保护野生型肿瘤细胞的攻击,射线灭活的EL-4/B7-1瘤苗作用减弱。结论：B7-1基因修饰的肿瘤疫苗可诱导体内的抗肿瘤免疫反应,导致肿瘤的部分根除,为基因修饰的肿瘤疫苗的临床应用提供了实验依据。     

HPV16E7E6抗原表位嵌合体DNA抗肿瘤疫苗的研究

目的:探讨HPV16 E7、E6抗原表位与HSP70 N端重组DNA疫苗抗肿瘤活性.方法:以重叠PCR将HPV16 E7基因N端60个氨基酸的编码序列与E6基因的10个(48～57)氨基酸的编码序列及HSP70 N端序列进行融合.以pcDNA3.0为载体,构建真核表达载体pcD-E76HSP.重组质粒免疫C57BL/6小鼠后,通过淋巴细胞增殖实验和细胞毒性杀伤实验研究该疫苗激发的细胞免疫反应及反应强度;观察该疫苗对C57BL/6小鼠TC-1肿瘤细胞移植瘤的治疗效果.结果:重组DNA疫苗免疫C57BL/6小鼠后,小鼠脾淋巴细胞体外增殖明显,并可诱导产生针对TC-1肿瘤细胞的特异性CTL反应;体内抑瘤试验显示该疫苗对HPV16病毒转化的TC-1细胞小鼠移植瘤的生长有抑制作用.结论:该疫苗能激发特异性细胞免疫反应,显著抑制HPV16转化的TC-1肿瘤细胞生长.     

顺铂联合DC疫苗对荷瘤小鼠抗肿瘤作用观察

目的:观察顺铂联合DC疫苗对荷瘤小鼠抗肿瘤作用。方法:用终浓度20μg/ml的顺铂处理体外培养的小鼠黑色素瘤B16或B16-hsp70L1细胞,24小时后,Western blot方法观察HMGB1、hsp70蛋白表达;用顺铂处理的B16或B16-hsp70L1细胞裂解液负载DC,LPS诱导成熟,流式细胞仪分析DCs表面MHCⅠ、ICAM-1、CD86的表达。制备荷瘤小鼠模型,给荷瘤小鼠经腹腔注射顺铂(100μg/只),瘤内注射DC疫苗(3×106/只),观察肿瘤生长曲线、荷瘤小鼠脾脏中肿瘤抗原特异性CD8+T淋巴细胞IFN-γ的分泌及CTL活性。结果:顺铂显著促进B16或B16-hsp70L1细胞HMGB1的表达,对hsp70蛋白表达影响不明显;顺铂处理的B16或B16-hsp70L1细胞裂解液负载DC后,MHCⅠ、ICAM-1及CD86表达率分别为41%、39%、42%和47%、41%、42%;顺铂联合DC疫苗不仅显著抑制荷瘤小鼠肿瘤增殖(P0.05),对荷瘤小鼠脾脏CD8+T淋巴细胞IFN-γ的分泌及CTL活性也有明显的提高。结论:顺铂处理的B16细胞裂解液可诱导DC活化;联合DC疫苗后不仅显著抑制荷瘤小鼠肿瘤生长,对肿瘤特异性免疫应答也具有一定的促进作用。     

美法仑治愈荷瘤小鼠的过程与TNFα的关系

目的探讨单一剂量的美法仑治愈荷瘤野生型C57BL/6小鼠的过程与肿瘤坏死因子α(TNFα)的关系。方法以3种遗传背景相同、肿瘤坏死因子受体1(TNFR1)基因型不同的TNFR1 / 、TNFR1 /-和TNFR1-/-C57BL/6小鼠为实验动物,皮下接种数量相同的小鼠淋巴瘤EL4细胞。接种瘤细胞后12d,给基因型不同的各组荷瘤小鼠腹腔内单次注射7.5mg/kg的美法仑。以荷瘤野生型C57BL/6小鼠(TNFR1 / )为对照,观察美法仑对荷瘤TNFR1 /-C57BL/6小鼠和荷瘤TNFR1-/-C57BL/6小鼠的治疗效应。结果在美法仑(7.5mg/kg)治疗后的1周内,基因型不同的各组荷瘤小鼠肿瘤消退的速度基本相同。在随后的2月内,荷瘤TNFR1 / 和TNFR1 /-C57BL/6小鼠的肿瘤结节逐渐消退、肿瘤治愈;而多数荷瘤TNFR1-/-C57BL/6小鼠的肿瘤结节缩小后又再次出现并逐渐长大、肿瘤复发。结论TNFα与美法仑治愈肿瘤的过程密切相关,其中美法仑的抗肿瘤作用与荷瘤小鼠TNFR1的表达无关,但在美法仑治疗后,机体预防或避免肿瘤复发方面需要TNFR1在机体细胞的表达,而不是在肿瘤细胞的表达。     

激发型4-1BB单抗联合凋亡肿瘤细胞负载的树突状细胞在恶性肿瘤免疫治疗中的作用

目的：研究激发型4-1BB单抗（2A）联合凋亡肿瘤细胞负载的DC（AP-DC）疫苗在小鼠B细胞淋巴瘤免疫治疗中的作用.方法：凋亡小鼠B细胞淋巴瘤细胞A20负载的DC用来制备AP-DC.A20荷瘤小鼠分别被注射AP-DC、2A单抗或二者联合.观察肿瘤生长情况及小鼠生存期.流式细胞术检测免疫治疗后荷瘤鼠脾脏T细胞的表型和胞浆内细胞因子;3H-TdR掺入试验检测T细胞体外增殖能力;ELISA法检测荷瘤鼠血清和脾脏T细胞培养上清中IL-2、IFN-γ和IL-10含量.结果：应用激发型4-1BB单抗2A或AP-DC疫苗对荷瘤小鼠开展免疫治疗,可抑制肿瘤生长,延长荷瘤鼠生存期,获得12.5%或25%的肿瘤完全缓解率.但二者联合应用,治疗效果更好,可获得62.5%的肿瘤完全缓解率,并且荷瘤鼠可长期生存.联合治疗后荷瘤鼠脾脏T细胞体外增殖更为显著,CD4^＋IFN-γ^＋细胞的比例也明显增加.IL-2和IFN-γ的分泌水平在联合治疗荷瘤鼠的血清和脾脏T细胞的培养上清中升高更明显,而IL-10的分泌则降低.结论：激发型4-1BB单抗和AP-DC在肿瘤免疫治疗中有协同作用.     

IL-12基因联合CD40L基因治疗小鼠黑色素瘤的实验研究

目的：观察腺病毒介导的小鼠白细胞介素12基因（AdmIL-12）和CD40配体基因（AdmCD40L）对小鼠黑色素瘤的抗肿瘤效果。方法：利用B16细胞皮下注射C57BL/6小鼠建立小鼠黑色素瘤模型，单独或联合应用分别携带小鼠IL-12基因和CD40L基因的重组腺病毒进行直接瘤内注射治疗，观察小鼠皮下肿瘤生长及成活情况。采用乳酸脱氢酶释放法检测荷瘤小鼠脾细胞CTL活性变化。结果：AdmIL-12和AdmCD40L在体内外均能有效表达；AdmIL-12能显著抑制荷瘤小鼠皮下肿瘤的生长并明显延长其生存时间，能显著增强荷瘤小鼠的脾细胞CTL杀伤活性。AdmCD40L的抗瘤效果不明显，但与Ad-mIL-12联合应用可明显提高抗肿瘤效果。结论：腺病毒介导的mIL-12基因对小鼠黑色素瘤有显著的治疗效果，且与CD40L基因联合应用能进一步提高抗肿瘤效果。     

HSP70多肽复合物修饰DCs疫苗抗胰腺癌荷瘤小鼠的实验研究

目的:探讨负载热休克蛋白70多肽复合物(HSP70-PC)抗原的树突状细胞(DCs)疫苗对胰腺癌荷瘤小鼠的免疫治疗作用.方法:采用低渗裂解、ConA-Sepharose亲和层析及ADP-Agarose亲和层析法,从小鼠胰腺癌(MPC83)肿瘤组织中纯化HSP70-PC,修饰小鼠骨髓来源的树突状细胞(DCs),制备树突状细胞HSP70多肽肿瘤疫苗,用MTT法检测混合淋巴细胞反应(MLR)中HSP70-PC致敏DC对CTL的增殖及活化效果;建立MPC83荷瘤小鼠模型,观察树突状细胞HSP70多肽肿瘤疫苗对荷瘤小鼠治疗的效果和小鼠存活期.结果:经上述方法分离、纯化获得了较高纯度的HSP70-PC蛋白质;HSP70-PC在1.5～2.0 μg/ml范围内可达到刺激树突状细胞最强效果,用HSP70-PC修饰的DCs能增强T细胞的增殖和活化能力;应用树突状细胞HSP70多肽肿瘤疫苗治疗荷瘤小鼠能显著抑制荷瘤小鼠肿瘤的生长,延长荷瘤小鼠存活期.结论:采用低压亲和层析柱可从胰腺癌瘤块中获得较高纯度HSP70多肽复合物,其修饰的DCs疫苗用于荷瘤小鼠免疫治疗有显著疗效,为临床胰腺癌生物免疫治疗奠定基础.     

腺病毒编码人TRP2修饰DC诱发抗小鼠黑色素瘤免疫的研究

目的比较腺病毒载体(Ad)介导人和小鼠酪氨酸酶相关蛋白2(tyrosinase-relatedpro-tein2,TRP2)修饰小鼠骨髓来源的树突状细胞(BM-DC)诱发抗小鼠黑色素瘤免疫的差异。方法Ad编码人或小鼠TRP2(AdhTRP2或AdmTRP2)体外感染小鼠BM-DC并体内皮下免疫C57BL/6小鼠,7d后取出被免疫小鼠脾细胞行体内细胞毒性T淋巴细胞杀伤试验(invivoCTL)和细胞内IFN-γ染色(ICS)分析CTL的杀伤活性和IFN-γ的产生;或给免疫后小鼠皮下接种小鼠B16.F10黑色素瘤细胞,观察荷瘤小鼠的成活情况。结果invivoCTL和ICS分析显示,AdhTRP2/BM-DC免疫小鼠,其6hCTL杀伤率为(98.7±1.2)%,IFN-γ产生的CD8+T细胞占总CD8+T细胞的(1.25±0.21)%;而AdmTRP2/BM-DC免疫的小鼠,其6hCTL杀伤率和产生IFN-γ的CD8+T细胞比例分别为(28.6±6.3)%和(0.24±0.06)%。荷瘤试验表明,AdhTRP2/BM-DC免疫小鼠后1周皮下接种106B16.F10细胞,观察3个月100%的小鼠无瘤生长;而接种5×104B16.F10细胞至AdmTRP2/BM-DC免疫1周的小鼠,3个月后小鼠成活率仅为40%。结论Ad介导异种(人)TRP2较自身(小鼠)TRP2修饰的BM-DC更为有效地打破肿瘤免疫耐受、诱导强烈的抗黑色素瘤免疫反应,是一种高效的以DC为基础的肿瘤疫苗。     

小鼠β-防御素2肿瘤疫苗的抗白血病作用研究

目的：探讨小鼠β-防御素2（MBD2）肿瘤疫苗的体内抗白血病作用及其机制。方法：小鼠体内接种转染MBD2的L1210小鼠白血病细胞（L1210-MBD2），观察细胞的致瘤性改变；对长期存活的小鼠用野生型L1210细胞进行二次攻击，探讨瘤苗的免疫保护作用；用照射L1210-MBD2瘤苗注射荷瘤小鼠，检测瘤苗的治疗效果。采用乳酸脱氢酶活性法测定接种瘤苗后小鼠脾脏细胞CTL及NK细胞毒活性，ELISA法检测脾细胞产生IFN-γ及IL-12含量。结果：转染MBD2使L1210细胞致瘤性明显降低（P〈0．05），80％小鼠长期生存；对照组小鼠全部死亡。用野生型L1210细胞二次攻击后100％dx鼠仍能长期生存。照射瘤苗能使50％的荷瘤小鼠长期生存，而对照组小鼠则全部死亡，两者之间具有显著性差异（P〈0．05）。接种MBD2瘤苗后，小鼠脾细胞对L1210的CTL及NK杀伤活性明显增强（P〈0．05），产生IFN-γ、IL-12水平显著升高（P〈0．05）。结论：L1210-MBD2瘤苗通过调节机体细胞免疫反应显示出较强的体内抗白血病作用，为淋巴细胞性白血病的免疫治疗提供了新策略。     

Elevated levels of antibodies against 70 kDa heat shock proteins in the sera of patients with HIV infection

Heat shock proteins (Hsp), especially 70 kDa heat shock protein (Hsp70) play an important role in the life cycle of HIV-1 virus. Hsp70 is overexpressed in HIV-infected cells and this is the most abundant Hsp associated with HIV virions. The aim of our study was to investigate whether HIV infection increases the extent of specific humoral immune response against Hsp70. The serum concentration of anti-Hsp70 IgG antibodies was measured in 47 HIV-infected patients, and 62 healthy, HIV-seronegative persons. Nineteen patients on highly active anti-retroviral therapy (HAART) were followed for 24 months in a longitudinal study. Anti-Hsp70 antibodies were measured by ELISA, using recombinant human Hsp70. Levels of anti-Hsp70 antibodies were significantly (P < 0.0001) higher in the HIV-infected patients (median: 1409 (25th-75th percentile: 1031-2214) AU/ml) than in healthy control subjects (626 (429-970) AU/ml). In 19 HIV patients, serum levels of anti-Hsp70 antibodies significantly (P < 0.001) decreased during 24 (11-41) months HAART (1309 (887-2213) AU/ml before and 640 (386-959) AU/ml during HAART), accompanied by viral load reduction and CD4+ count elevation. It is concluded that HIV-infection induces a marked increase in the anti-Hsp70 antibody levels, which is consistent with the enhanced expression of Hsp70 on the surface of HIV-infected cells and/or incorporation of the protein into the membrane of HIV virions.     

高粘血症大鼠心肌缺血缺氧时热休克蛋白,原癌基因表达的变化及意义

目的：研究高粘血症大鼠心肌发生缺血缺氧性损伤时原癌基因c－fos热休克蛋白（Hsp70）表达的变化及意义。方法：用免疫组化法（ABC法）检测高粘血症大鼠心肌组织和体外培养的心肌细胞缺氧后Hsp70和c－fos蛋白变化；用原位杂交法检测c－fosmRNA变化。用光镜、电镜观察心肌组织和心肌细胞的损伤。结果：发现c－fos蛋白在高粘血症大鼠心肌中明显增强，在体外培养的大鼠心肌细胞缺氧1h和4h后较对照组明显增强。c－fosmRNA表达也明显增强。上述变化与细胞损伤间呈正相关。结论：高粘血症引起的缺血缺氧可诱导c－fos表达增强和Hsp70增加，后者可能是心肌对缺血缺氧产生的应激反应产物。它们是一种早期防御代偿反应，并参与调节其他基因的变化。     

A rapid and reliable flow cytometric method for determining Hsp70 levels in tobacco protoplasts

Current methods to determine heat shock protein (Hsp) synthesis or accumulation in plant cells, such as Western blotting and biomet abolic labelling are either indirectly quantitative, labour-intensive or biohazardous. An optimal flow cytometric protocol was developed to measure the intracellular Hsp70/Hsc70 levels in tobacco protoplasts. After heat treatments, protoplasts were fixed in 2% paraformal dehyde-phosphate-buffered saline and dehydrated overnight in methyl cellusolve^TM, followed by permeabilization with Triton X-100 (0. 1% in Protoplast Wash Fluid). Immunolabelling of Hsp70/Hsc70 was done for 1 hour with a mouse monoclonal antibody and detected by;R-Phycoerythrin-conjugated goat anti-mouse IgG using flow cytometry. Flow cytometry detected a significant 1. 2-fold increase in Hsp70/Hsc70 accumulation (P < 0. 001) in protoplasts, while Western blotting, quantified by image anal ysis, showed induction under similar conditions but at lower significance (P < 0. 05). The coefficients of variance for flow cytometry and Western blotting were 30. 7 and 49. 8 respectively. Optimum temperature of heat-induced Hsp70/Hsc70 accumulation in tobacco protoplasts occurred at 40 °C. Flow cytometry is proposed as a quantitative, more reproducible and rapid alternative to Western blotting for the detection of Hsp70 accumulation in plant cells.     

A 14-mer peptide from HSP70 protein is the critical epitope which enhances NK activity against tumor cells in vivo

Heat shock protein 70 (Hsp70) has been found to play key roles in tumor immunity due its chaperone function of binding antigenic peptides. Here we report it can also stimulate NK cells in vivo, which is another role in Hsp70s' anti-tumor response. Injecting Hsp70 into mice increased splenic NK cell populations, which may be reason for anti-tumor effect of Hsp70. The Hsp70 14-mer peptide (aa450-463, TRD) was identified as the critical epitope for this stimulatory activity. It was the murine Hsp70 14-mer peptide TRD instead of the corresponding human Hsp70 14-mer peptide TKD that functioned in the mouse experimental model.     

Heat shock protein 70 inhibits shrinkage-induced programmed cell death via mechanisms independent of effects on cell volume-regulatory membrane transport proteins

Cell shrinkage is a ubiquitous feature of programmed cell death (PCD), but whether it is an obligatory signalling event in PCD is unclear. Heat shock protein 70 (Hsp70) potently counteracts PCD in many cells, by mechanisms that are incompletely understood. In the present investigation, we found that severe hypertonic stress greatly diminished the viability of murine fibrosarcoma cells (WEHI-902) and immortalized murine embryonic fibroblasts (iMEFs). This effect was attenuated markedly by Hsp70 over-expression. To determine whether the protective effect of Hsp70 was mediated via an effect on volume regulatory ion transport, we compared regulatory volume decrease (RVD) and increase (RVI) in control WEHI-902 cells and after increasing Hsp70 levels by heat shock or over-expression (WEHI-912). Hsp70 levels affected neither RVD, RVI nor the relative contributions of the Na⁺/H⁺-exchanger (NHE1) and Na⁺,K⁺,2Cl^–-cotransporter (NKCC1) to RVI. Hypertonic stress induced caspase-3 activity in WEHI cells and iMEFs, an effect potentiated by Hsp70 in WEHI cells but inhibited by Hsp70 in iMEFs. Osmotic shrinkage-induced PCD was associated with Hsp70-inhibitable cysteine cathepsin release in iMEFs and attenuated by caspase and cathepsin inhibitors in WEHI cells. Treatment with TNF- or the NHE1 inhibitor 5-(N-ethyl-N-isopropyl)amiloride (EIPA) reduced the viability of WEHI cells further under isotonic and mildly, but not severely, hypertonic conditions. Thus, it is concluded that shrinkage-induced PCD involves both caspase- and cathepsin-dependent death mechanisms and is potently counteracted by Hsp70.     

Efficient induction of a Her2-specific anti-tumor response by dendritic cells pulsed with a Hsp70L1-Her2(341-456) fusion protein

Heat shock proteins (HSPs) have been shown to interact with antigen-presenting cells (APCs), especially dendritic cells (DCs). HSPs act as potent adjuvants, inducing a Th1 response, as well as antigen-specific CD8(+) cytotoxic T lymphocytes (CTL) via cross-presentation. Our previous work has demonstrated that Hsp70-like protein 1 (Hsp70L1), a new member of the Hsp70 subfamily, can act as a powerful Th1 adjuvant in a DC-based vaccine. Here we report the efficient induction of tumor antigen-specific T cell immune response by DCs pulsed with recombinant fusion protein of Hsp70L1 and Her2(341-456), the latter of which is a fragment of Her2/neu (Her2) containing E75 (a HLA-A2 restricted CTL epitope). The fusion protein Hsp70L1-Her2(341-456) promotes the maturation of DCs and activates them to produce cytokines, such as IL-12 and TNF-α, and chemokines, such as MIP-1α, MIP-1β and RANTES. Taken together, these results indicate that the adjuvant activity of Hsp70L1 is maintained in the fusion protein. Her2-specific HLA-A2.1-restricted CD8(+) CTLs can be generated efficiently either from the Peripheral blood lymphocytes (PBL) of healthy donors or from the splenocytes of immunized HLA-A2.1/K(b) transgenic mice by in vitro stimulation or immunization with DCs pulsed with the Hsp70L1-Her2(341-456) fusion protein. This results in more potent target cell killing in an antigen-specific and HLA-A2.1-restricted manner. Adoptive transfer of splenocytes from transgenic mice immunized with Hsp70L1-Her2(341-456)-pulsed DCs can markedly inhibit tumor growth and prolong the survival of nude mice with Her2(+)/HLA-A2.1(+) human carcinomas. These results suggest that Hsp70L1-Her2(341-456)-pulsed DCs could be a new therapeutic vaccine for patients with Her2(+) cancer.     

Heat shock proteins form part of a danger signal cascade in response to lipopolysaccharide and GroEL

An increasing number of cell types, including peripheral blood mononuclear cells (PBMCs), have been demonstrated to release heat shock proteins (Hsps). In this paper we investigate further the hypothesis that Hsps are danger signals. PBMCs and Jurkat cells released Hsp70 (0.22 and 0.7 ng/10(6) cells, respectively) into medium over 24 h at 37 degrees C. Release of Hsp70 was stimulated 10-fold by GroEL (P < 0.001) and more than threefold by lipopolysaccharide (LPS) (P < 0.001). Although Hsp60 could be detected in the medium of cells cultured at 37 degrees C for 24 h, the low rates of release were due probably to cell damage. Significant release of Hsp60 was observed when Jurkat cells were exposed to GroEL (2.88 ng/10(6) cells) or LPS (1.40 ng/10(6) cells). The data are consistent with the hypothesis that Hsp70 and Hsp60 are part of a danger signalling cascade in response to bacterial infection.     

Effects of heat shock protein 70 (Hsp70) on arsenite-induced genotoxicity

Arsenic, a human carcinogen, is genotoxic, although its mechanism(s) of action for tumorigenesis is not well understood. Among the toxicity-related properties of this chemical are its clastogenic and aneugenic activities, as well as its capacity for inducing stress-response in the form of elevated heat shock protein (HSP) expression. In the present study, we evaluated the effects of Hsp70 expression on arsenite (As)-induced structural and numerical chromosome anomalies in human cells. Human MCF-7 Tet-off cells stably transfected with a pTRE/Hsp70-1 transgene construct were used to regulate Hsp70 levels prior to in vitro As exposures. Separate cultures of relatively high vs. low Hsp70-expressing cells were established. A cytokinesis block micronucleus assay with kinetochore immunostaining was used to detect micronuclei (MN) derived from chromosome breakage (K-MN) or loss (K+MN). These studies demonstrated significant increases in micronucleus frequencies in response to As following either a long exposure (5 or 10 microM for 46 hr), or short exposure (10 or 40 microM for 8 hr) protocol. Overall, the long protocol was more efficient in producing K+MN and cells with multiple MN. Overexpressing Hsp70 resulted in significant reductions in the percent of cells positive for MN for both the long and short As exposure protocols. Both K+ and K- types of As-induced MN were lower in cells with elevated Hsp70 as compared to cells without overexpression of Hsp70. We conclude that the dose and duration of As exposure influence the type as well as amount of chromosomal alteration produced and that inducible Hsp70 protects against both the clastogenic and aneugenic effects of this chemical.     

血管成形术后平滑肌细胞癌基因产物Fos及热休克蛋白—70的表达及意义

目的:研究血管成形术后平滑肌细胞中Fos、热休克蛋白—70的表达及意义.方法:将10只新西兰家兔随机分为正常对照组(血管数为n=4),血管成形术组(n=8),血管成形术+低分子量肝素组(n=8),以2F PTCA导管对两侧髂动脉进行血管成形术,术后1小时、2小时取血管成形后血管进行Fos、热休克蛋白—70免疫组化染色.结果:正常动脉内未见Fos表达,血管成形术后1小时部分平滑肌细胞阳性,2小时表达增多;正常动脉内热休克蛋白—70位于平滑肌细胞胞浆内,血管成形术后1、2小时平滑肌细胞核呈阳性;血管成形术+低分子量肝素组与单纯血管成形术组结果相同.结论:Fos于血管成形术后早期出现,与SMC增生迁移有关,低分子量肝素不影响此过程.首次发现血管成形术后热休克蛋白—70迅速增加,可能是一种对抗血管成形术损伤的保护机制.