氟尿嘧啶引起大鼠气管损伤修复过程中干细胞的定位

目的 气管干细胞的原位观察。方法 使用5-氟尿嘧啶(5-FU)造成大鼠离体气管环的严重损伤，采用光镜、PCNA免疫组织化学，以及Hoechst33342染色观察气管黏膜的修复过程。结果 5-Fu作用12h后，气管上皮脱落，可见少量间隔分布的类似裸核的细胞呈钉状位于基底膜上，PCNA染色阴性(Go期细胞)，其中少数细胞Hoechst33342染色阴性。去除5-FU6h后，气管黏膜由扁平上皮覆盖；48h后，气管环恢复假复层纤毛柱状上皮。结论 5-Fu能杀死处于细胞周期的气管上皮细胞，对Go期细胞作用很小，残留于基底膜上的裸核样的Go期细胞中含有干细胞，其Hoechst33342染色阴性，并具有排出荧光染料的能力，正是这些细胞的增殖分化，修复了损伤的气管环。     

Quantitative determination of binding of anthracycline antibiotics with DNA

Research Institute of Experimental Diagnosis and Treatment of Tumors, Oncologic Scientific Center, Russian Academy of Medical Sciences, Moscow. Troitsk Branch, I.V. Kurchatov Institute of Atomic Energy, Moscow Region. (Presented by Academician of the Russian Academy of medical Sciences, N. N. Trapeznikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 113, No. 6, pp. 636–638, June, 1992.     

P4对双氧水诱导SH-SY5Y细胞凋亡的保护作用

目的：研究P4对双氧水诱导SH-SY5Y细胞凋亡的影响。方法体外培养SH-SY5Y细胞,建立双氧水诱导SH-SY5Y细胞凋亡的模型,给予P4进行干预。应用Hoechst染色,测定细胞凋亡率。结果10uM的双氧水24 h可以使SH-SY5Y细胞凋亡率达到(56.33±13.17)%。然而,给予P4后,SH-SY5Y细胞的凋亡率明显减低,P4加双氧水组与双氧水组对比差异有统计学意义(P<0.05)。结论P4对SH-SY5Y细胞的凋亡有保护作用。     

Persistence of side population cells with high drug efflux capacity in pancreatic cancer

AIM： To investigate the persistence of side population （SP） cells in pancreatic cancer and their role and mechanism in the drug resistance. METHODS： The presentation of side population cells in pancreatic cancer cell line PANC-1 and its proportion change when cultured with Gemcitabine, was detected by Hoechst 33342 staining and FACS analysis. The expression of ABCB1 and ABCG2 was detected by real- time PCR in either SP cells or non-SP cells. RESULTS： SP cells do exist in PANC-1, with a median of 3.3% and a range of 2.1-8.7%. After cultured with Gemcitabine for 3 d, the proportion of SP cells increased significantly （3.8% ± 1.9%, 10.7% ± 3.7%, t = 4.616, P = 0.001 〈 0.05）. ABCB1 and ABCG2 expressed at higher concentrations in SP as compared with non-SP cells （ABCB1： 1.15 ± 0.72, 5.82 ± 1.16, t = 10.839, P = 0.000 〈 0.05; ABCG2： 1.16 ± 0.75, 5.48 ± 0.94, t = 11.305, P = 0.000 〈 0.05）, which may contribute to the efflux of fluorescent staining and drug resistance. CONCLUSION： SP cells with inherently high resistance to chemotherapeutic agents do exist in pancreatic cancers, which may be candidate cancer stem cells contributing to the relapse of the tumor.     

Side population cells in human cancers

Cancer stem cells (CSCs) are found in multiple tumor types. While the presence of surface markers selectively expressed on CSCs are used to isolate these cells, no marker or pattern of makers are known to prospectively identify CSCs in many tumor types. In such cases exploitation of stem cell characteristics can be used to identify CSCs and one such characteristic is the capacity to extrude dyes such as Hoechst 33342. Cell that exclude this dye are referred to as side population (SP) cells. These cells share characteristics of CSCs, specifically, they are enriched for tumor initiating capacity, they express stem-like genes, and they are resistant to chemotherapeutic drugs. Dye exclusion is a valuable technique as it identifies a unique population of cells with stem-like characteristics.     

侧群细胞与肿瘤干细胞研究进展

目的:总结国内外采用侧群细胞分析法(side populations analysis)研究肿瘤干细胞的现状。方法:应用检索PubMed数据库检索系统,以“侧群细胞“和“肿瘤干细胞“等为关键词,检索1996-01-2008-12侧群细胞法研究肿瘤干细胞的文献。资料选择:选择所有侧群细胞法研究肿瘤干细胞的文献。纳入标准:1)侧群细胞法分离肿瘤干细胞;2)侧群细胞法鉴定肿瘤干细胞。根据纳入标准,精选80篇文献,最后纳入分析36篇文献。结果:采用SP法可以有效的分离和富集大部分类型的肿瘤干细胞,但是某些肿瘤SP细胞不具有肿瘤干细胞特性,此外,SP法还存在细胞毒性的问题。结论:采用SP分析法研究肿瘤干细胞存在许多问题,但是当无法确认到某种类型的肿瘤干细胞的表面标志时,它仍然是分离和富集肿瘤干细胞的有效方法之一。     

Contribution of apoptosis in the cytotoxicity of the oxaliplatin-irinotecan combination in the HT29 human colon adenocarcinoma cell line

Interactions between the topoisomerase I inhibitor irinotecan (CPT-11) and the platinum derivative oxaliplatin (L-OHP) were investigated in HT29 colon cancer cell line. Synergism was observed when cells were simultaneously exposed to drugs or when cells were first exposed to CPT-11. Flow cytometric studies showed a G(2)/M accumulation when cells were exposed to the simultaneous and CPT-11-->L-OHP combinations whereas a persistent S phase delay was observed when cells were first exposed to L-OHP. We characterised the cytotoxic effect by assessing the induction of apoptosis. Irinotecan induced substantial DEVDase activity and poly(ADP-ribose) polymerase cleavage while this activity was moderate and delayed after exposure to L-OHP. Combination experiments showed a sequence-dependent onset of apoptosis, the CPT-11-->L-OHP schedule being the earliest and the most effective; on the other hand the apoptotic signaling generated by CPT-11 was partly inhibited in the simultaneous combination and in the L-OHP-->CPT-11 sequence. Cell death studies using a dual staining technique showed a shift from apoptosis to necrosis when combining these drugs at high concentrations. Synergistic interactions observed using CPT-11 before L-OHP may be linked to an early apoptotic signaling while the L-OHP-induced S phase block could account for the observed additive effect in the reverse sequence. An additional phenomenon might work towards synergism for the simultaneous combination.     

Colchicine induces apoptosis in organotypic hippocampal slice cultures

The microtubule-disrupting agent colchicine is known to be particular toxic for certain types of neurons, including the granule cells of the dentate gyrus. In this study we investigated whether colchicine could induce such neuron-specific degeneration in developing (1 week in vitro) and mature (3 weeks in vitro) organotypic hippocampal slice cultures and whether the induced cell death was apoptotic and/or necrotic. When applied to 1-week-old cultures for 48 h, colchicine induced primarily apoptotic, but also a minor degree of necrotic cell death in the dentate granule cells, as investigated by cellular uptake of the fluorescent dye propidium iodide (PI), immunostaining for active caspase 3 and c-Jun/AP-1 (N) and fragmentation of nuclei as seen in Hoechst 33342 staining. All four markers appeared after 12 h of colchicine exposure. Two of them, active caspase 3 and c-Jun/AP-1 (N) displayed a similar time course and reached a maximum after 24 h of exposure, 24 h ahead of both PI uptake and Hoechst 33342 staining, which together displayed similar time profiles and a close correlation. In 3-week-old cultures, colchicine did not induce apoptotic or necrotic cell death. Attempts to interfere with the colchicine-induced apoptosis in 1-week-old cultures showed that colchicine-induced PI uptake and formation of apoptotic nuclei were temporarily prevented by coapplication of the protein synthesis inhibitor cycloheximide. Application of the pancaspase inhibitor z-VAD-fmk almost completely abolished the formation of active caspase 3 protein and apoptotic nuclei induced by colchicine, but the formation of necrotic nuclei increased correspondingly and the PI uptake was unaffected. We conclude that colchicine induces caspase 3-dependent apoptotic cell death of dentate granule cells in hippocampal brain slice cultures, but the apoptotic cell death is highly dependent on the developmental stage of the cultures.     

Transient cochlear ischemia causes delayed cell death in the organ of Corti: an experimental study in gerbils

To elucidate whether ischemia-reperfusion can cause delayed cell death in the cochlea, the effects of transient cochlear ischemia on hearing and on neuronal structures in the cochlea were studied in Mongolian gerbils. Ischemia was induced by bilaterally occluding the vertebral arteries for 5 minutes in gerbils, which lack posterior cerebral communicating arteries. In gerbils, the labyrinthine arteries are fed solely by the vertebral arteries. Occlusion of the vertebral arteries caused a remarkable increase in the threshold of compound action potentials (CAPs), which recovered over the following day. However, 7 days after the onset of reperfusion, the threshold began to increase again. Morphologic changes in the hair cell stereocilia were revealed by electron microscopy. The number of nuclear collapses was counted in cells stained for DNA and F-actin to evaluate the degree of cell death in the organ of Corti. Changes in spiral ganglion cell (SGC) neuron number were detected, whether or not progressive neuronal death occurred in the SGC. These studies showed that sporadic fusion of hair cells and the disappearance of hair cell stereocilia did not begin until 4 days after ischemia. On subsequent days, the loss of hair cells, especially inner hair cells (IHCs), and the degeneration of SGC neurons became apparent. Ten days after ischemia, the mean percentage cell loss of IHCs was 6.4% in the basal turn, 6.4% in the second turn, and 0.8% in the apical turn, respectively, and the number of SGC neurons had decreased to 89% of preischemic status. These results indicate that transient ischemia causes delayed hearing loss and cell death in the cochlea by day 7 after ischemia.