共查询到19条相似文献,搜索用时 187 毫秒
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目的 探讨LyGDI的表达在非小细胞肺癌细胞A549中的辐射抗性机制。方法 A549和作为对照的H460细胞分别受到0、2、4和6 Gy X射线照射后,克隆形成试验分析辐射抗性差异,Western blot分析LyGDI和辐射敏感性关键基因环氧合酶COX-2的表达。实时荧光定量PCR分析miR-34a以及miR-34b/c在A549和H460细胞中的表达。A549细胞中转染50 nmol/L的miR-34c成熟序列,观察其对A549细胞辐射抗性以及LyGDI和COX-2基因表达的影响。结果 LyGDI和COX-2在辐射抗性的A549细胞中的表达水平高于H460细胞,miR-34a以及miR-34b/c在两种非小细胞肺癌中低表达。转染miR-34c可抑制LyGDI、COX-2和Bcl-2以及激活p21的表达,增强A549细胞细胞的辐射敏感性(t=3.85、5.89、5.12,P<0.05)。结论 LyGDI诱导的COX-2的上调表达以及电离辐射效应miR-34家族的下调表达,是A549细胞辐射抗性的一个主要原因。 相似文献
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目的 研究2、4 Gy X射线照射后人肺腺癌细胞miR-424*体内、外表达以及非小细胞肺癌患者肺组织及血清中miR-424*的表达变化及其意义。方法 2、4 Gy X射线分别照射体外培养的A549细胞,以实时定量PCR(RT-qPCR)法检测A549细胞中miR-424*表达水平;用照射后的A549细胞制备裸鼠肺转移动物模型,检测裸鼠肺组织及血清中miR-424*的表达水平;收集肺癌患者肺组织及血清样本,检测miR-424*表达水平。结果 2、4 Gy X射线照射后1、2、12、24及48 h,miR-424*表达均显著升高(2 Gy:t=-45.886~-6.709,P<0.05;4 Gy:t=-29.087~-7.833,P<0.05);0、2、4 Gy照射后,miR-424*在裸鼠肺及血清中表达水平分别为空白对照组的9.72、8.58及4.7与11.93、9.22及8.99倍(t=-13.243~-3.052,P<0.05)。6/11例(54.5%)患者肺癌组织中高表达miR-424*,腺癌、鳞癌病理类型间检出率差异无统计学意义(P>0.05);43/84例(51.20%)肺癌患者与健康志愿者相比,血清miR-424*表达升高 1.97~17.71倍,其中腺癌患者血清检出率为39.1%(18/46),鳞癌患者血清检出率为65.8%(25/38),两种病理类型检出率差异有统计学意义(t=5.919,P<0.05);此外,84例肺癌患者中,miR-424*[JP3]在未接受放疗的肺癌患者血清中的阳性检出率为41.5%(22/53),显著低于接受放疗的肺癌患者血清的阳性检出率67.7%(21/31)[JP](t=5.387,P<0.05)。结论 2、4 Gy X射线照射可增加A549细胞miRNA-424*的体内、外表达水平,可能与增强A549细胞体内、外侵袭转移能力有关。肺癌患者中50%以上的肺癌组织及肺癌患者血清中miR-424*表达水平显著升高,可能与肺癌的病理类型及放疗相关。 相似文献
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目的 分析不同非小细胞肺癌(NSCLC)细胞对碳离子照射放射敏感性的影响,并探讨其相关的分子机制。方法 采用12C6+对肺腺癌A549细胞、鳞癌H520细胞和大细胞癌PGCL3细胞进行照射,吸收剂量分别为0、2、4和6 Gy。通过克隆实验检测3种细胞系的存活率,流式细胞术检测细胞的周期分布,利用Hoechst 33258染色检测细胞的凋亡率,实时RT-PCR方法检测细胞内DNA-PKcs基因的表达。结果 2、4、6 Gy照射后,A549、H520和PGCL3细胞的存活率明显下降,其中A549细胞辐射敏感性最低,其次是PGCL3细胞,H520细胞辐射敏感性最高。受照射后细胞均出现G2/M期阻滞与凋亡,且随剂量的升高呈现上升的趋势。受照射H520与PGCL3细胞的阻滞率(t=4.813、20.738、25.654和t=2.790、2.977,P<0.05)和凋亡率(t=8.579、14.289、15.244和t=3.785、5.098、8.105,P<0.05)明显高于A549细胞。受照射细胞DNA-PKcs表达明显上调,A549细胞最高,其次是PGCL3细胞,H520细胞最低;并且随着剂量的升高,DNA-PKcs的表达呈现下降趋势。2、4 Gy照射后H520和PGCL3细胞DNA-PKcs的表达明显低于A549细胞(t=7.782、3.689和t=3.889、2.814,P<0.05)。结论 不同NSCLC细胞对12C6+离子的放射敏感性不同,H520鳞癌细胞最高,A549腺癌细胞最低。肺腺癌A549细胞放射敏感性较低可能与高表达的DNA-PKcs参与NHEJ途径修复DNA双链断裂有关。 相似文献
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目的 探讨microRNA-491-5p(miR-491-5p)在缺氧诱导的滋养细胞凋亡中的作用及其对子痫前期的影响。方法 选取人绒毛膜滋养层细胞,分为4组:对照组、缺氧组、缺氧+miR-491-5p mimic组和缺氧+miR-491-5p inhibit组。采用细胞活力染色检测滋养细胞凋亡情况,qRT-PCR检测miR-491-5p的表达,TargetScan数据库预测miR-491-5p的靶基因,双荧光素酶报告基因实验验证miR-149-5p与B-细胞淋巴瘤因子2样蛋白2基因(BCL2L2)的靶向关系。miR-491-5pmimic和inhibitor分别转染滋养细胞后,qRT-PCR检测miR-491-5p的表达,Westernblotting检测BCL2L2蛋白的表达改变,细胞活力染色、Western blotting、流式细胞术检测滋养细胞凋亡情况。结果 与对照组比较,缺氧组滋养细胞凋亡率明显增高(P<0.001),miR-491-5p表达明显增高(2.784±0.214 vs. 1.000±0.000,P<0.01);生物信息学预测与双荧光素酶检测报告实验显示... 相似文献
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Radiation-induced apoptosis in human non-small-cell lung cancer cell lines is secondary to cell-cycle progression beyond the G2-phase checkpoint 总被引:2,自引:0,他引:2
Stuschke M Sak A Wurm R Sinn B Wolf G Stüben G Budach V 《International journal of radiation biology》2002,78(9):807-819
PURPOSE: To characterize the relationship between cell-cycle progression and radiation-induced apoptosis in NSCLC cell lines with different p53 status. MATERIALS AND METHODS: Cell lines with functional (H460, A549) and non-functional p53 (H661 and H520) were irradiated with 20 Gy. Multiparameter flow-cytometry was used to follow the progression of synchronized cells through the cell cycle after irradiation. RESULTS: Delayed apoptosis was observed after cell-cycle progression beyond the G2 block, either in the late G2/M-phase of the same cell cycle being irradiated (H661, H520) or in the G1-phase of the subsequent cell cycle (H460, A549). The apoptotic fraction in H661 and H520 was 60-80% at 144h after irradiation, higher than in A549 and H460 (5 and 35%, respectively). As an alternative to apoptosis in cells cycling beyond the G2 restriction point, hyperploid cells were generated by all cell lines. Inhibition of cell-cycle progression through the G2/M-phase efficiently reduced the induction of late apoptosis. After irradiation in S-phase, 50-60% of cells with functional p53 remained arrested at the G2 restriction point until 144 h post-irradiation, while only 20% of the H661 or H520 did so. CONCLUSIONS: These data characterize radiation-induced apoptosis in NSCLC cell lines as a removal pathway of clonogenically inactivated cells secondary to cell-cycle progression beyond G2/M, and is unlikely to be a critical factor for cellular radiation sensitivity. 相似文献
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目的:研究低剂量辐射诱导小鼠睾丸生精细胞凋亡的适应性反应。方法:应用原位末端标记(TUNEL)和常规HE染色法分别结合光镜定量地观察75mGyX射线照射诱导小鼠睾丸生精细胞在生精周期中凋亡的适应性反应。结果:当1.0、2.0或3.0Gy(攻击剂量,D2)X射线照射前6h给予75mGy(诱导剂量,D1)预照射时明显减轻D2对睾丸精原细胞和精母细胞的凋亡损伤作用,而对精子细胞影响不明显,当1.0、1.5、2.0、2.5、3.0Gy(D2)X射线照射前3、6、12、24h给予75mGy(D1)预照射时,发现当D2剂量较小(1.0、1.5、2.0Gy)时,精原细胞和精母细胞的凋亡百分率减少出现较早,较明显,而且持续时间较长;反之,当D2剂量较大(2.5和3.0Gy)时,精原细胞和精母细胞的凋亡百分率减少只有照后6h)出现,而且不显著。结论:低剂量电离辐射可以诱导精原细胞和精母细胞凋亡的适应性反应,并与D1和D2间隔时间及D2剂量有关。 相似文献
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Kato F Ootsuyama A Nomoto S Kondo S Norimura T 《International journal of radiation biology》2001,77(1):13-19
PURPOSE: To obtain evidence that the p53 gene is indispensable for reduction of high teratogenic risk of radiation at a high dose-rate to zero risk by lowering the dose-rate. MATERIALS AND METHODS: Wild-type p53(+/+), heterozygous p53(+/-) and null p53(-/-) mice were exposed to gamma-rays at high or low dose-rates during days 9.5-10.5 of gestation. The incidence of malformations and prenatal deaths was studied. Frequencies of cells dying by apoptosis were measured during or after protracted irradiation. RESULTS: After irradiation with 2 Gy, the frequency of apoptotic cells increased to 20% for p53(+/+) mice and did not increase at all for p53(-/-) mice. For p53(+/+) mice, 2 Gy y-rays induced 70% malformations when given at 1.06 Gy/min, but no malformations above the control when given at 1.2 mGy/min. In contrast, after irradiation of p53(-/-) foetuses with 2 Gy at 1.2mGy/min, the incidence of malformations increased 12% above control levels. CONCLUSION: Foetal irradiation with 2 Gy at 1.2 mGy/min was not teratogenic for p53(+/+) mice but teratogenic for p53(-/-) mice. This indicates that the p53 gene is indispensable for a threshold effect in the risk of radiation at low doses or dose-rates. 相似文献
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Induction of cytogenetic adaptive response of somatic and germ cells in vivo and in vitro by low-dose X-irradiation 总被引:3,自引:0,他引:3
The cytogenetic adaptive response induced by low-level radiation was studied using human and rabbit lymphocytes in vitro and bone marrow cells and germ cells in vivo. The inductive dose of X-rays was 10 mGy for the in vitro studies at a dose rate of 10 mGy/min, and 2, 10, 50, 75 and 100 mGy for the in vivo studies at a dose rate of 50 mGy/min. The challenging dose was 1.5 Gy X-rays for the in vitro experiments and 0.65 or 0.75 Gy for the in vivo experiments at a dose rate of 0.44 Gy/min. The results reported here, in addition to those that have appeared in the literature, show the following characteristics documented for the first time: (1) 10 mGy could induce the adaptive response in human as well as rabbit lymphocytes irradiated not only in G1, S and G2 phases, but also in the Go state; (2) although the induced adaptive response could only last three cell cycles, it could be revived when the inductive dose was repeated after the third cell cycle; (3) the adaptive response could be induced by low-dose X-rays in somatic cells, both in vitro (lymphocytes) and in vivo (bone marrow cells), and also in germ cells (spermatocytes); (4) the magnitude of the adaptive response induced by whole-body irradiation was found to be dose-dependent--the lower the inductive dose the more the reduction of the frequency of chromatid aberrations following the challenging dose. 相似文献
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目的 观察多次低剂量辐射(LDR)对糖尿病(DM)大鼠脾细胞凋亡和免疫因子的影响。方法 大鼠随机分为对照组、DM组和DM+LDR组;剂量分别为25、50和75 mGy,共照射15次;照射后4周,采用流式细胞术检测脾细胞凋亡和TCRα β百分数的变化,酶联免疫吸附法(ELISA)检测血清和脾细胞培养上清IL-2含量的变化。结果 与对照组相比,DM和DM + LDR两组大鼠体重均下降,尤以DM组明显。DM+LDR组大鼠血糖水平虽明显高于对照组(t25=23.321、 t50=18.329、 t75=9.23,P<0.01),但显著低于DM组(t25=3.574、 t50=4.593、 t75=5.577,P< 0.01)。同时发现:与对照组相比,DM+LDR各组脾细胞凋亡增加,其中DM+50 mGy组增加明显(t50=4.102,P<0.01)。血清IL-2含量也增加,但是差异均无统计学意义。脾细胞培养上清IL-2含量明显下降(t25=7.778、 t50=7.411、 t75=8.325,P<0.01)。与DM组相比,DM+LDR各组脾细胞凋亡和TCRα β百分数均明显降低(凋亡:t25=4.772、 t50=3.346、 t75=6.778;TCRα β:t25=3.381、 t50=5.807、 t75=2.356,P<0.05~P<0.01)。血清IL-2含量呈下降趋势;脾细胞培养上清IL-2含量均有升高趋势。结论 多次LDR能够削弱糖尿病造成的大鼠体重减轻和血糖升高,降低糖尿病所致的脾细胞凋亡,并能调节脾脏免疫因子,改善其失衡状态。 相似文献
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目的 观察低剂量辐射对恶性肿瘤患者自体CIK细胞增殖、表型和杀伤活性的影响,为临床应用CIK细胞过继免疫治疗提供依据。方法 取10例恶性肿瘤患者外周血,常规分离出单个核细胞,用不同细胞因子培养诱导CIK细胞。培养10 d后,以30、50、80、100和200 mGy X射线照射,24 h后采用3H-TdR掺入法检测对CIK细胞增殖的影响;流式细胞术检测对CD3+CD56+表型CIK细胞百分率的影响;3H-TdR释放法检测对其杀伤活性的影响。采用3H-TdR释放法检测80 mGy X射线照射对自体CIK细胞在12、24、48和72 h杀伤活性的影响,及80 mGy连续照射3 d对CIK细胞杀伤活性的影响。结果 CIK细胞增殖活性与对照组(0 mGy)相比均有明显增高(t =2.2、3.5、3.3和2.2, P <0.05)。50、80和100 mGy组的CD3+CD56+细胞的百分率均有显著性增高(t =2.3、4.2和2.4, P <0.05)。CIK细胞接受LDI,80 mGy组和100 mGy组与对照组(0 mGy)相比,CIK细胞杀伤活性均有显著性增高(t =3.3和2.3, P <0.05)。80 mGy照射后24 h,CIK细胞的杀伤活性出现高峰,为(54.2±5.0)%(t =3.2, P <0.01),48和72 h下降到正常水平。80 mGy连续照射3 d,24和48 h CIK细胞杀伤活性分别为(55.2±5.3)%和(61.9±4.4)%,72 h达到最高水平为(67.2±5.7)%(t =2.6、4.7和5.7, P <0.05)。结论 低剂量辐射对肿瘤患者CIK细胞显示兴奋效应,具有临床应用前景。 相似文献
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目的 研究低剂量X射线照射诱导小鼠睾丸生精细胞凋亡的适应性反应。方法 昆明雄性小鼠接受诱导剂量(D1,75mGy)和攻击剂量(D2,1.0,2.0和3.0Gy)全身照射。通过不连续泛影葡胺密度梯度离心法分离小鼠睾丸组织不同种类生精细胞,流式细胞术(FCM)检测各类生精细胞凋亡。结果 当D2照射前6h给予D1预照射时明显减轻D2对睾丸精原细胞和精母细胞凋亡的损伤作用,而对精子细胞和精子影响不明显。当D1和D2间隔3,6,12和24h,发现D2剂量较小(1.0和2.0Gy)时,精原细胞和精母细胞的凋亡百分率减少出现较早、较明显,而且持续时间较长;反之,D2剂量较大(3.0Gy)时,精原细胞和精母细胞凋亡百分率变化不明显。结论 低剂量X射线照射可以选择性诱导小鼠睾丸精原细胞和精母细胞凋亡的适应性反应,并与D1和D2间隔时间及D2剂量有关。 相似文献
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Delayed vascular injury after single high-dose irradiation in the rat brain: histologic immunohistochemical, and angiographic studies. 总被引:13,自引:0,他引:13
PURPOSE: To investigate structural and functional changes in rats after focal brain irradiation by using histologic, immunohistochemical, and angiographic methods. MATERIALS AND METHODS: Sixty rats were irradiated stereotactically with photons from a 15-MeV linear accelerator. Two collimators and single doses ranging from 20 to 100 Gy were used to treat stereotactically defined areas of 3.7- and 4.7-mm cross section (80% isodose) in the right frontal lobe. The dose-response relationship for the end-point necrosis at 19 months revealed a mean tolerance dose (D50) of 34.2 Gy (standard errors: +4.1, -3.7 Gy). Histologic, immunohistochemical, and angiographic examinations were performed to evaluate delayed radiation effects. RESULTS: All animals irradiated with 100 Gy developed radiation necrosis after 9 months. Microangiography and immunohistochemical fluorescence staining of the endothelial cells revealed dose-dependent vascular dilatation and rarefaction. Animals irradiated with 20-50 Gy showed no morphologic changes after 9 months. With irradiation of 30-50 Gy, histologic vascular changes that increased with dose were found after 19 months. At that time, no changes were detected after irradiation with 20 Gy with both field sizes and after irradiation with 30 Gy and the 2-mm collimator. Radiation-induced functional disturbances of the brain vasculature could be demonstrated by extravasation of contrast medium by using a microangiographic technique. CONCLUSION: The observed effect had a definite dependence on dose, volume, and time after treatment. 相似文献