诺维本联合放射对人肺腺癌细胞的杀伤作用

[目的]研究诺维本联合放射对人肺腺癌细胞(PAA)的杀伤作用.[方法]应用四唑盐比色试验(MTT)检测诺维本对PAA细胞生长的抑制率和时间效应;流式细胞术检测细胞周期及凋亡情况.[结果]不同浓度(20、40、60、80、100μmol/L)的诺维本作用24h后对细胞生长的抑制率分别为6.12%、18.80%、53.91%、77.10%和90.20%,ID50为59.10μmol/L;诺维本对细胞生长的抑制作用在高浓度时具有明显的时间依赖性;从流式细胞术的细胞周期分析结果发现,经诺维本作用后G2/M期细胞的比例明显增加;单纯药物组的凋亡在24h出现,单纯放射组在放射后12h出现明显的凋亡小峰,药物放射联合组出现凋亡的时间更早,凋亡峰亦更明显,各组细胞在不同时间内的平均凋亡百分数分别为:对照组5.362±4.123,单纯放射组6.523±6.214,单纯药物组9.985±9.023,药物联合放射组18.100±8.965,药物联合放射组与其它3组相比,P均＜0.05.[结论]诺维本联合放射对人肺腺癌细胞有协同杀伤作用.     

高Z重金介质的肿瘤放疗增敏效应研究现状

目的：探讨高Z重金介质的放射剂量增强效应及其应用于肿瘤放疗增敏的研究历史、当前进展与未来发展方向。方法：全面检索高Z介质表面/界面的剂量效应及其用于肿瘤放疗增敏的早期研究和最新报道。针对近年来开展的重金介质放疗增敏相关研究,按照放疗射线类型和增敏效应研究手段分别进行总结述评,以把握该领域的发展历史和研究现状,并对现存的问题进行讨论和展望。结果：目前针对高Z重金介质的放疗增敏研究主要包括质粒DNA辐照、体外细胞辐照、动物肿瘤模型试验以及剂量学模拟等手段。针对传统X-γ射线放疗的增敏效应研究最为深入,针对同步辐射放疗、质子重离子放疗等先进放疗技术的重金增敏研究也有开展。研究结果已充分证明了重金介质的放射增敏效应及其用于肿瘤放疗增敏的可行性,为临床前试验的进一步开展提供了重要的理论和实验依据。结论：高Z重金介质的肿瘤放疗增敏效应研究近年来取得了较快的进展,部分研究已从增敏效应验证进入放疗试验的增敏参数优化和作用机理研究阶段,为实现其在临床肿瘤放疗中的应用,增敏效应的微观作用机理是必须深入研究的重要课题。     

The Interaction Between Radiation and Complexes of Cis-Pt(II) and Rh(II): Studies at the Molecular and Cellular Level

Summary

A range of Rh(II) carboxylates and cis-Pt(II) complexes have been examined for their ability to increase the radiation sensitivity of aerobic and hypoxic V79 cells in vitro. The transition metal complexes sensitize in both air and nitrogen, with the greater effect generally occurring in nitrogen. The cis-Pt(II) complexes only show small levels of sensitization with dose modification factors (DMFs) of no more than 1·2. In contrast, the Rh(II) complexes can give DMFs of 2·0. Radiation chemical experiments show the transition metal complexes to have substantially lower redox potentials than metronidazole and, in addition, neither type of complex undergoes electron transfer reaction or adduct formation on interaction with radicals derived from DNA bases. Thus, the inorganic complexes do not operate by mechanisms similar to those occurring with electron affinic or stable free radical sensitizers. The increase in radiation sensitivity for cells treated with the Rh(II) carboxylates, but not the cis-Pt(II) complexes, is attributed to the ability of the Rh compounds to deplete intracellular thiols. Further, the efficiency of sensitization by the Rh(II) complexes and their ability to interact with cellular thiols depends upon the nature of the carboxylate ligand and follows the order butyrate > propionate > acetate > methoxyacetate. The differences between the carboxylates may be due to differences in drug uptake. A combination of the Rh(II) complexes with misonidazole given to hypoxic cells irradiated in vitro gives an additive response. However, it was not possible to demonstrate a similar effect in tumours in mice given the combination of Rh(II) methoxyacetate and the misonidazole analogue RSU 1070.     

甲氟喹对胶质瘤细胞的放射增敏作用

目的:研究甲氟喹对胶质瘤细胞的放射增敏作用,并对其机制进行初步探索。方法:取指数生长期的胶质瘤U251细胞,采用CCK-8检测法研究甲氟喹作用后U251细胞的存活率;细胞克隆形成实验评估甲氟喹对U251细胞的放射增敏效果;流式细胞技术检测甲氟喹联合X射线作用后U251细胞的活性氧水平和细胞凋亡率,探索联合作用下U251细胞的死亡机制。结果:甲氟喹对胶质瘤细胞具有良好的放射增敏效果,其对U251细胞的最大放射增敏比为1.64。X射线联合甲氟喹作用于U251细胞后,细胞的凋亡水平增加,活性氧水平增加,活性氧抑制剂谷胱甘肽能抑制X射线联合甲氟喹作用诱导的U251细胞凋亡。结论:甲氟喹对U251细胞有放射增敏作用,其作用机制可能为通过增加细胞活性氧水平、诱导细胞凋亡导致放射敏感性增加。     

Tumor radiation response enhancement by acoustical stimulation of the vasculature

We have discovered that ultrasound-mediated microbubble vascular disruption can enhance tumor responses to radiation in vivo. We demonstrate this effect using a human PC3 prostate cancer xenograft model. Results indicate a synergistic effect in vivo with combined single treatments of ultrasound-stimulated microbubble vascular perturbation and radiation inducing an over 10-fold greater cell kill with combined treatments. We further demonstrate with experiments in vivo that induction of ceramide-related endothelial cell apoptosis, leading to vascular disruption, is a causative mechanism. In vivo experiments with ultrasound and bubbles permit radiation doses to be decreased significantly for comparable effect. We envisage this unique combined ultrasound-based vascular perturbation and radiation treatment method being used to enhance the effects of radiation in a tumor, leading to greater tumor eradication.     

Mutations in the FHA-domain of ectopically expressed NBS1 lead to radiosensitization and to no increase in somatic mutation rates via a partial suppression of homologous recombination

Ionizing radiation induces DNA double-strand breaks (DSBs). Mammalian cells repair DSBs through multiple pathways, and the repair pathway that is utilized may affect cellular radiation sensitivity. In this study, we examined effects on cellular radiosensitivity resulting from functional alterations in homologous recombination (HR). HR was inhibited by overexpression of the forkhead-associated (FHA) domain-mutated NBS1 (G27D/R28D: FHA-2D) protein in HeLa cells or in hamster cells carrying a human X-chromosome. Cells expressing FHA-2D presented partially (but significantly) HR-deficient phenotypes, which were assayed by the reduction of gene conversion frequencies measured with a reporter assay, a decrease in radiation-induced Mre11 foci formation, and hypersensitivity to camptothecin treatments. Interestingly, ectopic expression of FHA-2D did not increase the frequency of radiation-induced somatic mutations at the HPRT locus, suggesting that a partial reduction of HR efficiency has only a slight effect on genomic stability. The expression of FHA-2D rendered the exponentially growing cell population slightly (but significantly) more sensitive to ionizing radiation. This radiosensitization effect due to the expression of FHA-2D was enhanced when the cells were irradiated with split doses delivered at 24-h intervals. Furthermore, enhancement of radiation sensitivity by split dose irradiation was not seen in contact-inhibited G0/G1 populations, even though the cells expressed FHA-2D. These results suggest that the FHA domain of NBS1 might be an effective molecular target that can be used to induce radiosensitization using low molecular weight chemicals, and that partial inhibition of HR might improve the effectiveness of cancer radiotherapy.     

黄芪多糖对人鼻咽癌CNE-1细胞的放疗增敏及上皮间质转化的作用

目的:采用黄芪多糖(APS)与放射治疗(IR)联用,研究APS对人鼻咽癌CNE-1细胞的放疗敏感性及上皮间质转化(EMT)的作用机制。方法:采用细胞计数(CCK-8)法检测不同质量浓度APS(0,6.25,12.5,25,50,100,200 g·L-1)对CNE-1细胞的细胞毒性;克隆形成实验计算12.5 g·L-1APS与不同放射剂量(0,2,4,6 Gy)联用后对CNE-1细胞的存活分数(SF),利用线性二次方程数学模型(LQ)根据SF值绘制放射敏感曲线;细胞划痕和transwell小室实验分别检测各组细胞的迁移和侵袭能力;流式细胞仪检测各组细胞的凋亡情况;蛋白免疫印迹法(Western blot)检测各组细胞的EMT标记物、凋亡标记物以及蛋白激酶B/细胞外调节蛋白激酶(Akt/ERK)通路蛋白的表达水平。结果:克隆形成实验和放射敏感曲线结果表明,非毒性剂量12.5 g·L-1APS与4 Gy放射剂量联合给药可以明显增加CNE-1细胞的放疗敏感性;与空白组及IR组比较,APS与IR联用可以抑制CNE-1细胞的迁移和侵袭能力(P0.05),明显增加CNE-1细胞的凋亡率(P0.05)。与空白组及IR组比较,APS与IR联用可以显著下调间质型钙黏蛋白(N-cadherin),p-Akt和p-ERK蛋白表达水平,明显上调上皮型钙黏蛋白(E-cadherin),B淋巴细胞瘤-2相关X蛋白(Bax)和半胱天冬氨酸蛋白酶-3(Caspase-3)蛋白表达水平(P0.05)。结论:APS与IR联用可以抑制CNE-1细胞的迁移和侵袭,增加放疗引起的细胞凋亡,其可能通过抑制EMT和Akt/ERK通路有关。     

中西药物对肺腺癌放射增敏基因表达谱初步研究

目的:利用基因芯片技术研究扶正增效方、甲硝唑对肺腺癌放射增敏基因表达谱,筛选出中西药物对放射增敏的差异表达基因及其共同表达基因。方法:捉取中西药物加放射组癌组织及单纯放射组癌组织RNA,分别用Cy5-dCTP或Cy3-dCTP标记,再与38500点人基因芯片杂交,筛选中西药物加放射组与单纯放射组差异表达基因。结果:中药加放射组与单纯放射组差异表达基因857条,上调349条,下调508条,其中39条GeneBank中登录,差异显著基因中15条表达上调,21条表达下调,分别为凋亡、转录调节、信号转导、细胞周期、DNA损伤与修复、免疫等相关基因;差异极显著基因1条,为THRA。西药加放射组与单纯放射组差异表达基因47条,已知显著差异基因3条,分别为DNA损伤与修复、转录调节、信号转导等相关基因。只有RARA基因在中西药放射组出现差异表达。结论:中西药物放射增敏存在不同的基因表达谱,说明中西药物放射增敏基因机制不尽相同,筛选出的特异表达基因和共同表达基因为进一步研究放射增敏药物开发和建立放射增敏动物模型具有重要意义。     

甘氨双唑钠联合放射治疗中晚期鼻咽癌临床研究

目的:观察甘氨双唑钠(sodiumglyci-didazole,CMNa)在中晚期鼻咽癌放射治疗中的作用。方法:60例中晚期鼻咽癌患者随机分观察组(CMNa 放疗)和对照组(单纯放疗组)各30例。CMNa静脉滴入,每次0·75g,每周1、3和5用药,用药后1h内放疗。放疗采用常规外照射方案。结果:鼻咽原发灶CR率在观察组和对照组分别是93%和73%,两组差异有统计学意义,χ2=4·320,P=0·0377。颈淋巴结CR率两组分别是90%和63%,两组差异亦有统计学意义,χ2=5·963,P=0·0146。两组毒副反应如皮肤、黏膜、消化道反应及血白细胞下降等差异无统计学意义,P>0·05。结论:CMNa联合放射治疗可提高鼻咽癌的肿瘤局部控制率,而毒副反应不增加。